A sun that never moves (Worldbuilding brainstorming)

[Seto]

The system is Pathfinder, but I'm looking for thematic input over mechanical. This is the story of a mistake I made when I became a GM 5 years ago, and musings about how I could fix it now.

So, now that I have a few more years of experience under my belt (mostly playing in Golarion), I've started idly thinking about reworking the first setting I made back when I started GMing. Its main worldbuilding gimmick was that the sun never moved. (Or, yeah, precisely speaking, the Earth did not rotate around the sun nor on its own axis). The result being that there was no day/night cycle: so to speak, it was always midnight at a certain geographical point, always 4PM at another, etc.). I implemented it in a very direct and rudimentary fashion to keep it short and intuitive: since the Sun rises in the East and sets in the West IRL, in my world it "got earlier" when you traveled eastward and "later" when you traveled westward. There were still climactic differences even at the same "hour": it got warmer in the south and colder in the north.

Looking back upon it now, I think the main benefit of this idea is that it's thematically and symbolically pretty strong. It allows me to geographically represent the passage of time, the different stages of life and its evolution, both on an individual scale (from birth to death) and on a much larger scale: in the far East, wild untamed jungles give birth to primal life and wondrous creatures. If you go far enough, you reach the nigh-unpopulated lands of Dawn, permanently bathed in a white light. In the far West, vegetation becomes sparse and large vermin roam the earth. If you go far enough, you reach the Cursed Lands where the Undead Lords are locked in an perpetual struggle over vast magnitudes of blighted lands plunged in eternal darkness.
Standard PC races inhabit the middle of the day (from around 10AM to 6PM). Elves, as an older and "wilder" race, live in the forests of the late morning. In ages past, Orcs have been driven to live in a southern, unforgiving desert at high noon (over time they lost the "light sensitivity" trait). Dwarves live in the huge mountain chain that divides the continent, around 12 to 2 PM. The realms of Men (and also Halflings and some Gnomes) extend roughly from 2 to 6PM - of course, there are some big differences between eastern and western kingdoms. There's Nordic and Celtic-inspired tribal cultures in the far north bordering the sea. Then the northern half of the continent has your standard human-centric medieval-European fantasy kingdoms. The southern half is semi-desertic and has no central power, but it boasts several Free Cities that are bustling centers of trade, visited by Halfling and Gnomish nomadic merchants. There's also a tropical archipelago far south, loosely inspired from Polynesia.

It's full of clichés, but that doesn't bother me. It's meant to be a standard fantasy world, a kitchen-sink (but a manageable one), with a little bit of every climate and societal organization.

So I'd like to keep my "fixed hours" gimmick, because 1- it's the one thing that makes my setting the slightest bit memorable, 2- I think it resonates really well symbolically, and is a pretty strong start when it comes to large-scale worldbuilding. Its big weak point, though, is that I have trouble translating it to small-scale worldbuilding, ie. how does it affect everyday life, how did every society adapt to it etc. Which makes it just that: a gimmick. What happened when I GMed in that setting some years ago was that it felt unnecessary and tacked on. The players, and even I sometimes, kept forgetting that it was always day, because it wasn't really relevant to the adventure we were playing. Having to remember "I wait for nightfall and go to sleep... Uh, I mean I wait a few hours, close the curtains to block the light and go to sleep", instead of being the cool unique fantasy flavor I had envisioned, became an annoying cognitive load. Doubly so because it broke verisimilitude: obviously, if it's sunny 24/7, it should matter! Society should be noticeably different from what we know!
So if I'm ever to rework that setting, that's something I have to fix properly.

If you can't tell already, I'm very much the kind of person who builds settings by first painting very broad strokes, and then filling in concrete details, rather than the "start small and expand outwards" method. So I'm asking help from those in the Playground more detail-oriented than I. How would my gimmick shape societies? (I'm mostly looking at the human kingdoms and halfling/gnomish semi-nomadic traders here).

- One obvious thing would be protection. From light, from the heat. Agriculture would have to adapt in some way, perhaps with marquee-like structures around smaller fields, in order to control shade thanks to a removable cloth "roof". I know nothing about that field, so maybe shade has no bearing on it and I'm saying nonsense, I don't know. Also, in order to sleep, people would have thick curtains and boarded windows everywhere.

- Speaking of sleep, maybe there wouldn't be a clear cycle that everybody follows. Since it's always day, after all, usual daytime activities are accessible at all hours. So the day could be roughly divided between three periods of 8 hours, and the population, at least in organized communities, could take turns sleeping. Maybe they'd be divided according to their profession, or on the contrary, they'd make sure that someone from every profession would be up in every 8 hours-period. We need names to call those periods, though, or else it's bound to be confusing. Let's take a kingdom. Imagine that the King sleeps in the first period. Since someone needs to be ready to govern and respond at all times, the Prince stays awake in that time, and sleeps in the second period. During the third period when both are awake, the Councelor sleeps - that way, he can be awake to give counsel to the Prince when the King is sleeping, then keep the King apprised of what the Prince has done.
So there's "the King's time", followed by "the Prince's time", then "the Counselor's time", and that's the division of a day. The general population could refer to themselves as "Kingers", "Princers" or "Counselors" depending on which 8-hour period of the day they sleep. Noisy businesses would have to operate away from sleeping people. That could be cool. I don't know, just spitballing here.

What other fun, crazy ideas could we have? :smallbiggrin:

TLDR: If it was perpetually 3PM or something (no morning, no dusk, no night), how would that affect your average fantasy kingdom? What about a society of semi-nomadic traders?

[Telonius]

For practical purposes, a few classes would be affected. Clerics usually have a specific time of day that they "typically" pray to their deity. That's going to have to shift. Some Binder vestiges have rules about time of day, too.

Culturally, it's going to be very, very different. There would be no "seasonal renewal" festivals like harvest, solstice, and so on. Any mythology would be a whole lot less about things occurring in seasonal cycles. The cyclical stuff would be more about the sleep and waking cycle and labor; daily, personal renewal rather than seasonal, natural renewal.

[Celestia]

The big thing is that unless there is some powerful magic at play, most of the planet will be completely uninhabitable. The sun-facing side will be a blazing inferno with temperatures in the range of 100-300°C (or maybe even higher). Meanwhile, the dark side would be an ice ball well below zero. The only part that could support life would be the thin band of twilight.

Now, the gods could change this and make the whole planet livable. In that case, I'd expect there to be a strong religious culture, likely focusing around two chief deities: the sun god(dess) who keeps the planet from burning and the moon god(dess) who keeps the planet from freezing. There could also be a dual cultural system in place based around these two that could be either cooperative or antagonistic. You might also add in a god(dess) of the twilight who acts as a neutral intermediary between the other two.

[Grey Watcher]

The big thing is that unless there is some powerful magic at play, most of the planet will be completely uninhabitable. The sun-facing side will be a blazing inferno with temperatures in the range of 100-300°C (or maybe even higher). Meanwhile, the dark side would be an ice ball well below zero. The only part that could support life would be the thin band of twilight.

Now, the gods could change this and make the whole planet livable. In that case, I'd expect there to be a strong religious culture, likely focusing around two chief deities: the sun god(dess) who keeps the planet from burning and the moon god(dess) who keeps the planet from freezing. There could also be a dual cultural system in place based around these two that could be either cooperative or antagonistic. You might also add in a god(dess) of the twilight who acts as a neutral intermediary between the other two.

A potential twist on your idea: it's the Moon deity that keeps the Sun from burning everything and the Sun deity that keeps the Moon from freezing everything. Each would like nothing more than to plunge the world into extremes, but they're so evenly matched that neither can do much more than moderate the other's influence over their half. Or maybe the influence of the Other Side is welcome, because each likes having a functional world and knows that, without the moderating influence, that wouldn't be possible. Or maybe some weirdly idiosyncratic or ambiguous mix.

Still, that's all very high up metaphysics that may or may not be relevant to the players. But the point is, you can play with whether and to what degree these forces might be friendly or antagonistic to each other.

[RatElemental]

The obvious word for the three periods that springs to my mind is "shift" or maybe "watch."

You could have it vary by culture, maybe the Gnomes work in shifts (first shift, second shift, third shift), while humans work in watches (King's Watch, Prince's Watch, Vizier's Watch).

As far as culture goes, no day cycle doesn't necessarily mean no seasonal cycle. In our world it would, but maybe in this case the planet's orbit is somehow much more elliptical than ours, such that it really does vary in distance from the sun enough to result in seasonal differences throughout the year. The entire world would be in the same season all at once in such a case, while the cursed darklands never change seasons, but it's at least plausible.

This would mean that, rather than not rotating at all, the planet is tidally locked with the sun however.

[John05]

Climate

Besides what Celestia mentioned, it won't just be scorching hot in the sunniest area, there will be consistent and high winds coming in from cold areas on all sides. Over the decades, this area would end up collecting enormous amounts of sand and dust creating huge dunes. It's completely uninhabitable even to many subterranean races. Even drow want to come out once in a while to collect slaves. The winds and dust will end up even covering a lot of natural caves.

Lack of precipitation will also be a problem because the water in colder areas won't evaporate as much. You might need to come up with other sources of water such as gates to planes of water or massive natural springs. The only water I can see collecting in the Sun lands would be underground. Even more so in the sunniest areas, since it would naturally sink underneath treeless hills of sand and dust.

Large bodies of open water will generally be still due to lack of winds in the coldest areas where water will naturally flow to (where water will end up collecting over time). You also lack solar tides. Lunar tides are twice as strong so the moon (or moons) could potentially make up for that. As can gates to hell/abyss or other sources of magical/unnatural heat to cause turbulence/winds.

[John05]

Civilization/Culture

Regarding that "thin band of twilight"... I think it might not be so thin, and we can still end up with a bit of variety given variations in terrain. I.e. mountainous regions where the cold from higher altitude can negate some of the heat from constant sun. They can also offer shade to some places. Also, you'd have constant wind going from colder areas to warmer areas, which offers some relief from the heat, so it's not like the sunnier areas of the band won't have some mitigating factors.

I imagine that most humanoid cultures that do live in that habitable ring area will end up being more lawful, because they're accustomed to predictability and stability. They have reliable and stable source of light (no need to collect fuel for lighting; even for darker areas, just fix a mirror to deflect some sunlight at that place) and very stable wind. Water will be relatively constant. Either enough of it, or not enough of it. Not much chance for variation.

Hell, imagine the NIMBYs living in these places. "Oh no you don't build that tower! Not In My Back Yard. I've lived here for 25 years, and not once has my house been under shadow!

It's even hard to plan surprise attacks on strongholds in these areas, because there's no nighttime. The productivity is also higher since certain industries will be up and running all day.

In general societies full of lawful people who can tolerate this stagnant environment would be more likely to flourish.

[Biggus]

"I wait for nightfall and go to sleep... Uh, I mean I wait a few hours, close the curtains to block the light and go to sleep"

- One obvious thing would be protection. From light, from the heat. Agriculture would have to adapt in some way, perhaps with marquee-like structures around smaller fields, in order to control shade thanks to a removable cloth "roof". I know nothing about that field, so maybe shade has no bearing on it and I'm saying nonsense, I don't know. Also, in order to sleep, people would have thick curtains and boarded windows everywhere.

- Speaking of sleep, maybe there wouldn't be a clear cycle that everybody follows. Since it's always day, after all, usual daytime activities are accessible at all hours. So the day could be roughly divided between three periods of 8 hours, and the population, at least in organized communities, could take turns sleeping. Maybe they'd be divided according to their profession, or on the contrary, they'd make sure that someone from every profession would be up in every 8 hours-period.

All of this would only apply if the world once turned, but doesn't now. If it's always been this way, people wouldn't need darkness to sleep because they'd never have known natural darkness. Plants would be adapted to the constant light and heat so wouldn't need protection.

More than this, the concept of a day wouldn't exist, or a year for that matter. You'd need to decide what people used to measure time in pre-technological societies. Breaths for short periods, lifetimes of various living things for long periods?

One thing which would make a huge difference to the world is: is there a moon and if so, does it move? If it does move, presumably timekeeping would be based on a lunar cycle. If it doesn't move, where is it in the sky? Which parts of the world can see it?


The big thing is that unless there is some powerful magic at play, most of the planet will be completely uninhabitable. The sun-facing side will be a blazing inferno with temperatures in the range of 100-300°C (or maybe even higher). Meanwhile, the dark side would be an ice ball well below zero. The only part that could support life would be the thin band of twilight.


Presumably creatures with the fire subtype would be the only living things on the most sunward side, and those with the cold template on the dark side. Real-world creatures couldn't live in either, certainly.



Hell, imagine the NIMBYs living in these places. "Oh no you don't build that tower! Not In My Back Yard. I've lived here for 25 years, and not once has my house been under shadow!


This brings up another major point: when you get fairly near to the "twilight zone" between dark and light, shadows will become very long. A mountain range will create a huge area of permanent cold and dark behind it, and even building a high wall would block the sun for a long distance, potentially killing anything on the sunless side.

[RNightstalker]

Society can do well without light. Look at the Underdark. They still have their cycles to measure the passage of time.

Building off of the question about the moon, if done right the orbit of the moon would provide eclipses on the sunny side to help cool things off, provide a time of rest.

[Biggus]

Society can do well without light. Look at the Underdark. They still have their cycles to measure the passage of time.


What cycles do they use?

[Karl Aegis]

You've got no way of protecting yourself against diurnal predators. They can rest whenever they want. You can't approach without them noticing. You can't run away faster than they can chase you. They're big enough that you can't build fortifications to keep them out before they try to eat you. I'm imagining absolutely gigantic apex predators supplemented by photosynthesis devouring everything they see. There is no urbanization. There are no kingdoms. There is only retreat into the night where you try to replenish your numbers, where the equally dangerous nocturnal predators lurk. There is no hope, only beasts.

[Saintheart]

In terms of real-world analogues, the sort of planets that are indeed in a situation where their suns never move for them are those worlds which are tidally locked (https://en.wikipedia.org/wiki/Tidal_locking) to their stars, just as the Moon is tidally locked to the Earth. In terms of how conditions would be on such a planet, take a look here (https://arxiv.org/ftp/arxiv/papers/1405/1405.1025.pdf). Essentially, life only flourishes along the literal twilight zone, where it's a perpetual sunrise or sunset. For fictional examples where this takes place, the webpage that must not be referenced (https://tvtropes.org/pmwiki/pmwiki.php/Main/TidallyLockedPlanet) is a good start.

[legomaster00156]

Worth noting that such a concept has been played with. I suggest using it for inspiration.

https://pathfinderwiki.com/wiki/Verces

[rel]

Let's see...

There is always light. So far fewer light sources are needed. This means less jobs connected to making them which affects the names people will likely have; less people called wicker for example because there is less need for candles.

A lot more windows, skylights and the like to take advantage of the constant light. Maybe even areas open to the sky like courtyards or rooftop gardens incorporated into architecture. Unless a space needs to be dark expect it to be kept bright. Bedrooms probably have no windows or a few small ones for example.

For travelers, blocking out the light when they want to sleep is almost more necessary than blocking cold and rain. An awning and eye mask might be the signs of a traveler instead of the traditional tent and cloak.

no seasons (I assume) and constant light means plants grow really well so there is plentiful food.
Maybe a focus on foods that can be eaten raw since fires are no longer needed for light and less necessary for heat. summer salads, cold soups, steak tartar and sashimi, that sort of thing become daily fare with cooked food like roasts and baked bread being reserved for special occasions. foods that rely on darkness like mushrooms are probably less common and so highly prized.

Without any specific cycle to match everything to I can see societies becoming a lot more individualistic and chaotic. People sleep when they feel tired for as long as they want to, work as they chose and so on.
Having no way to synchronize (assuming accurate clocks and watches are rare and expensive) people often interact by leaving messages for one another or noting the other persons schedule and arriving at the right time.
Practically, shops are open at different times but have something like a library book return flap so you can 'post' orders which the owner will fill when he opens.
How tired someone is becomes more of a random personality trait for NPC's, you have people who just woke up rubbing shoulders with those ready to hit the sack.
Sure people that work or live together manage to coordinate but it's a huge hassle so you only do it if you have to. Waking Together is a courtship ritual where you figure out the sleep schedule of someone you fancy and match it.

The only long term cycle that really exists (since you can't count seasons or even days) is the motion of the spots and blemishes on the sun. Astronomers study these with light boxes and smoked glass and use them to track the passage of time for important projects. Their results are somewhat reliable.
The lay person measures time when they need to (say for the making of cheese by counting 'sleeps' (about a day) or 'by growth' watching the growth of a suitable plant. A seedling trussed to a marked dowel is a common fixture in spaces used for time sensitive activity

sunburn is a concern in some areas. Broad hats often feature in fashion and the creation of protective unguents, a 'screener' is an uncommon but known job. Plants and animals that protect from the sun or alleviate burn feature in lists of folk remedies. Alongside purported cures for boils and colds.

How this all looks to the adventurer on the ground:


you wake up and head to the general store, the shops entire front is open to provide light and there are windows in the roof that the owner is closing. The owner seems lethargic and mentions he is closing shortly; he's had a long day.
Then you head over to the smith. She hasn't opened yet but asking a local tells you she will be opening soon. so you head to the alchemists to buy some healing potions, The alchemists is an odd building with very few windows, only 4 can be seen on the street facing side and some of these are even shuttered. Your wizard remarks that certain alchemical ingredients are light sensitive. It's closed anyway but you peruse the catalogue out front and leave an order, pushing an envelope with a list of your selections, your address and some gold through a slot in the door. Then you head back to the smiths and get your swords sharpened. You stop for a breakfast of finely minced raw meat, herbs and spices at a food shop and eat under the open sky. You return to the inn you are staying and wait for the alchemist to stop by. She arrives with your order and even throws in some complimentary centaurhoof, a herb that soothes sunburn.
Gathering your belongings and making final preparations you leave the town and begin traveling. After a few hours travel you begin to feel tired so you stop for a meal of fruits and grain soaked in beer then stop for a rest. It hasn't rained recently and the ground is dry so you bind your eyes and sleep in the shade beneath a tree.

[Ramza00]

In terms of real-world analogues, the sort of planets that are indeed in a situation where their suns never move for them are those worlds which are tidally locked (https://en.wikipedia.org/wiki/Tidal_locking) to their stars, just as the Moon is tidally locked to the Earth. In terms of how conditions would be on such a planet, take a look here (https://arxiv.org/ftp/arxiv/papers/1405/1405.1025.pdf). Essentially, life only flourishes along the literal twilight zone, where it's a perpetual sunrise or sunset. For fictional examples where this takes place, the webpage that must not be referenced (https://tvtropes.org/pmwiki/pmwiki.php/Main/TidallyLockedPlanet) is a good start.

Recent XKCD, 2202 Earth-Like Exoplanet





https://imgs.xkcd.com/comics/earth_like_exoplanet.png

Hidden Hover Text: Fire is actually a potential biosignature, since it means something is filling the atmosphere with an unstable gas like oxygen. If we find a planet covered in flames, it might be an indicator that it supports life—or used to, anyway, before the fire.

Explain XKCD does a good job of explaining how living on these exoplanets is hard.

https://www.explainxkcd.com/wiki/index.php/2202:_Earth-Like_Exoplanet

Now Exoplanets are not that bad to live on if you are already have a habitable planet elsewhere and you are going to the exoplanet to colonize for tech can mitigate some of the downsides. The problem is why would you want to go to the exoplanet when Earth is so grand in comparison, or there are other ways to live in space. Perhaps the gravity well of an exoplanet is not worth it if you could in theory colonize an asteroid and spin it to create localized gravity and so on. What is the "value" of the exo-planet that makes it worth colonizing? Then again an exo-planet may make more sense than living on Mars or one of the further gas giant moons.

[Crake]

The big thing is that unless there is some powerful magic at play, most of the planet will be completely uninhabitable. The sun-facing side will be a blazing inferno with temperatures in the range of 100-300°C (or maybe even higher). Meanwhile, the dark side would be an ice ball well below zero. The only part that could support life would be the thin band of twilight.

Now, the gods could change this and make the whole planet livable. In that case, I'd expect there to be a strong religious culture, likely focusing around two chief deities: the sun god(dess) who keeps the planet from burning and the moon god(dess) who keeps the planet from freezing. There could also be a dual cultural system in place based around these two that could be either cooperative or antagonistic. You might also add in a god(dess) of the twilight who acts as a neutral intermediary between the other two.

There's actually quite a bit of research on tidally locked planets and their potential for inhabitability and this is actually rather incorrect. People vastly underestimate the conductive power of water, and while the sun facing side may indeed reach unlivable (by our standards) temperatures, going over 100 celcius is unlikely if there's any water around, though the further inland you get, the hotter it becomes, it may reach the 100 degrees level, but that's well within living standards for supernatural fire creatures with even a tiny amount of fire resistance, perfectly reasonable for a magical setting. Likewise, the "thin" band of habitability is actually rather large, going from roughly 105 degrees away from the sun to about 45 degrees from the sun, with the most comfortable zone being about 85 to 55, still a rather large band of livability. Everything further than that becomes a frozen waste, but even that is quite livable for anything with a minor amount of cold resistance.

I can't remember the exact place I found the research, but my gaming group discussed this exact kind of setting, and we spent a LOT of time doing research and even found hypothetical models of such a planet in our research.

[ZamielVanWeber]

This also assumes this is a properly tidally locked planet like anything we have. The Beastlands has an eternal day, twilight, and night layer each and suffers none of these issues so the planet could have (epic/deific) magic protecting it or even be on a demi-plane that has different rules from the material.

[Celestia]

There's actually quite a bit of research on tidally locked planets and their potential for inhabitability and this is actually rather incorrect. People vastly underestimate the conductive power of water, and while the sun facing side may indeed reach unlivable (by our standards) temperatures, going over 100 celcius is unlikely if there's any water around, though the further inland you get, the hotter it becomes, it may reach the 100 degrees level, but that's well within living standards for supernatural fire creatures with even a tiny amount of fire resistance, perfectly reasonable for a magical setting. Likewise, the "thin" band of habitability is actually rather large, going from roughly 105 degrees away from the sun to about 45 degrees from the sun, with the most comfortable zone being about 85 to 55, still a rather large band of livability. Everything further than that becomes a frozen waste, but even that is quite livable for anything with a minor amount of cold resistance.

I can't remember the exact place I found the research, but my gaming group discussed this exact kind of setting, and we spent a LOT of time doing research and even found hypothetical models of such a planet in our research.
Well that's cool. Makes the setting even better then, especially if you're going for a competitive deities angle. Then you could have events where one temporarily incapacitates the other, making their half of the world unbearable but still somewhat livable. The neutral deity could also be a water deity that helps mediate the other two with water, cooling the sun side and warming the moon side.

[Piggy Knowles]

Though it's science fiction rather than fantasy, a novel came out this year that explored societies on a tidally locked planet (The City in the Middle of the Night by Charlie Jane Anders). Might be a decent read if you're looking for ideas. I feel like a lot of it could be adapted effectively to a fantasy world.

[Zaq]

Wasn’t this a background premise in Word Realms? That might be worth checking out for an existing take on the concept. Word Realms is a great game that you should play anyway, so I recommend searching the Google machines for it.

They referred to directions as “dawnward” and “duskward,” which I like quite a bit.

Also, lots of “creatures of the night” are going to be pretty affected, since they’re based on the fantasy/mythology of a planet that has very different assumptions about the day/night cycle. Won’t get too many vampires or other sun-vulnerable undead in the dawnward realms, for instance. Lycanthropes, on the other hand, might be drawn to the dawnward realms if they want to stay in humanoid form, or they might be drawn to the duskward realms if they prefer being in beast form.

[Psyren]

Worth noting that such a concept has been played with. I suggest using it for inspiration.

https://pathfinderwiki.com/wiki/Verces

^ This - Verces is an official example of a tidally locked planet in PF/SF. So at least one answer to "what kind of society would develop" is "one like that."

The Vercites that live there are able to change eye and skin pigmentation at-will, allowing them to regulate the radiation they absorb when going from the sunny half (Fullbright) to the night half (Darkside) or staying in the thin habitable band between.

[OGDojo]

alright so as a twist to this, perhaps the extreme cold and heat has driven the whole world underground where mages have reinvented the day/night cycle and now the whole world exists inside cave systems that are constantly at battle with the drow and other creatures of the underdark since the creatures of the surface have moved underground into their precious territory. and a couple of your campaigns in said world could venture to the surface where creatures of extreme hot and cold roam around the world and you have to either avoid or fight them. and on that thin band where the temperature is perfect, you could have a lost civilization of people that thrived :smallsmile:

[Elkad]

Asimov's classic short story Nightfall is relevant as well.

Alternately, you could also have the sun move very slowly (over many years, say 1° per year, so you'd have a century or so in one spot if you moved drastically when the time was up). So sunlit civilization would have to keep migrating west to stay in the daylight. I seem to remember reading another story that used this as a premise, but I have no idea of the name/author. You'd have a constant cycle of move west, war with whatever is there, settle and defend your territory for a century, then mobilize again.

[King of Nowhere]

it's actually uncertain what climate would be like, as there are many theories that can conflict with each other.

Crake is correct that atmospheric circulation would keep the temperature acceptable in a fairly large band. but additional concerns are the water and wind cycle.
water evaporates from the hot areas and condense in cold areas. this could lead to all the water of the world accumulating in the cold pole, leaving the rest a barren desert.
in the real world we have something similar with antartica, which accumulated kilometers of ice that way until the ice cap sublimates as fast as it deposits. And a lot of the ice that deposits on the continent slides on the sea from the galciers. this mechanism works because antartica is not too big compared to the rest of the world. I have no idea what would happen if a good third of the planet was colder than antartica. I don't think anyone knows for sure
this is also affected by air circulation; antartica would be nowhere near as cold without the circumpolar oceanic current, which exists because there is an uninterrupted sea circling the world around antartica. the place was much warmer when the magellan strait was still closed.

as for air circulation, there would be huge convective movements of air mixing it from hot and cold regions. but would they be stable, steady and predictable winds, or would they be chaotic and giving rise to frequent storms that would make our worst hurricanes look like gentle breezes in comparison?

as for society, assuming the climate is not too disruptive, there wouldn't even be a concept of "day". or anything like an accurate calendar. people wouldn't have dates or hours, not unless they had accurate time-keeping technology. it would be a mess for historians.
crops would be adapted to it, and people too. probably the agricultural yield would be great for our standards, because of how constant sun and wheather. but they wouldn't have much concept of passing time. you ask peoople how old they are, they wouldn't know. there wouldn't be a year, nor a way to measure one. how long ago was some battle, some important event? anything past "when my grandmother was a child" is fog of times.

[legomaster00156]

If there is a concept of time passage, it isn't based on a day/night cycle, at least. There could still be a (relatively modern, compared to day/night) concept of time based on rotation around the sun itself. One example could be, in a world with an elliptical orbit like Earth, a passage of time recorded in distance from the sun. It would be more useful for scholars than the average person.

[Biggus]

It occurs to me that if you're using the tidally locked planet concept rather than an actual stationary planet, in the dark and deep twilight regions there could be concept of a year, because it would be the point at which the stars return to the same position.

[Crake]

It occurs to me that if you're using the tidally locked planet concept rather than an actual stationary planet, in the dark and deep twilight regions there could be concept of a year, because it would be the point at which the stars return to the same position.

An elliptical orbit could also simulate "seasons" to a degree.

[Elkad]

You could also track time via moon(s).