Is illusionary warmth protective against cold?

[SangoProduction]

Let's say you have a Complex Hallucination (https://www.d20pfsrd.com/magic/all-spells/c/complex-hallucination), which includes "thermal effects."

So, lets say that they hallucinate a campfire... ok. OK. Fine. Yeah, it doesn't protect against cold in any way, other than comfort, does it?
Well, I guess that was the essence of the question. Does that alleviation of discomfort have any mechanical consequences?

[Jack_Simth]

Let's say you have a Complex Hallucination (https://www.d20pfsrd.com/magic/all-spells/c/complex-hallucination), which includes "thermal effects."

So, lets say that they hallucinate a campfire... ok. OK. Fine. Yeah, it doesn't protect against cold in any way, other than comfort, does it?
Well, I guess that was the essence of the question. Does that alleviation of discomfort have any mechanical consequences?

Complex Halluination specifically:
Is an Illusion(phantasm) (https://www.d20pfsrd.com/magic#TOC-Illusion):

Phantasm: a phantasm spell creates a mental image that usually only the caster and the subject (or subjects) of the spell can perceive. This impression is totally in the minds of the subjects. It is a personalized mental impression, all in their heads and not a fake picture or something that they actually see. Third parties viewing or studying the scene don’t notice the phantasm. All phantasms are mind-affecting spells.(Emphasis added)

In my mind, it'd be like giving someone a shot of whiskey to warm them up. Makes them feel better, but doesn't actually work. If anything, puts them at greater risk (DM's friend, -2 to related checks) because they're not reacting like they would without it (shivering, pulling their cloaks tighter around themselves, and so on).

[Bohandas]

The only ways I can think of where an illusion would provide protection against the weather is either:

A.) The illusion has the [shadow] descriptor and is thus partly real

or

B.) If some factor has caused the weather to manifest itself as a creature such as some kind of elemental (or possibly fey), leaving it vulnerable to being deceived

[spectralphoenix]

I would also add that disbelieving the illusion would be probably become very easy if the real temperature was cold enough to cause damage. I don't think an illusion of a campfire could hide the fact that the creature is getting frostbite, liquids not part of the illusion are freezing, food isn't cooking, and so forth.

[OracleofWuffing]

I'm reminded of an old webcomic featuring a room filled with illusory air. PCs got sucked into the room when they opened a door and suddenly couldn't hear anything. One of them made a save and was the only person in the room to notice that everyone else was turning blue and gagging, and had to demonstrate there was no air by trying to activate a flaming sword- which couldn't keep alight.

Unfortunately, I think it was for an older D&D edition where illusions had different rules. At least it's a starting point.

[Inevitability]

I'm reminded of an old webcomic featuring a room filled with illusory air. PCs got sucked into the room when they opened a door and suddenly couldn't hear anything. One of them made a save and was the only person in the room to notice that everyone else was turning blue and gagging, and had to demonstrate there was no air by trying to activate a flaming sword- which couldn't keep alight.

Unfortunately, I think it was for an older D&D edition where illusions had different rules. At least it's a starting point.

There's this vaguely D&D-themed webnovel (Worth The Candle, really good but also a huge read), where one of the villains is an illusionist (with 'illusion magic' roughly based on souped-up major images: it can generate custom synchronized impressions for any sense, including sense of balance and pain). It's exactly as much of a pain as it sounds like it'd be.

Anyway, I'm pretty sure the above stunt would work perfectly fine under that system.

[Ashtagon]

I'd say that each time they suffer some kind of new penalty or damage effect (or are required to save against the same) against the environment, they would be allowed a new save against an illusion that presents them as being in an environment that does not require that save or cause that damage/penalty. In effect, the save/damage/penalty constitutes the interaction with the illusion that grants the save to disbelieve the illusion.

The illusion won't actually protect against the environment at all, but they will act as if it does (within the limits of physical ability) until they disbelieve. Until they disbelieve, they will blame any environmental penalties on just about anything else.