In Pathfinder, I know there are things like Cold Weather Outfits and Heatstones to minimize the effects of cold weather exposure.
If a party is forced to sleep outside in below-freezing temperatures, are there any rules for how things like blankets, tents, and campfires can help?
It seems like they would help, but I've not found anything conclusive on how helpful they would actually be. Considering as temperatures are generally the lowest at night, and how dangerous cold weather exposure can be, it's pretty important to have the means available to survive in such conditions.
Best Answer
Most of this is handled (Though admittedly not in detail) in the environmental rules for cold:
A lot of this is vague and open to interpretation. Partly, that's because it's not a focus for most campaigns. There's a lot of GM's who'll just let you travel through cold areas with either Endure Elements or a Cold Weather Outfit.
Note that all saves happen because of a lack of protection. If the party uses Endure Elements, that stops them from having to make Fortitude checks unless circumstances go really extreme. But if they don't, then the GM will have to make a ruling on how much blankets and such help against exposure. For example, you could make a save every two hours instead of one, or give a minor bonus on those saves. Or when using sufficient blankets and sharing body heat, saves might not be required at all.
Somewhat less objective, I'd personally rule that having two out of three (tent, blanket, campfire) would stop you from having to make saves during the night. Campfire can help you warm up, and therefore heal from the exposure non-lethal damage while traveling.
It's important to keep in mind what is fun for your gaming table. Does your party like having to micromanage a lot? Then make a detailed ruling so they know how to prepare, and how to act it all out.
Are they just there to slay dragons and get loot? You might want to just handwave it away.