5e spells

[pukunui]

There may be spells that create heat, or shelter, or warmer clothing. However most of those that I can think of are on the more arcane-type spell lists.

If the bard has prestidigitation, they could use it to keep everyone's clothes warm for an hour at a time. That ought to at least give advantage on the save.

 

[Storyteller Hero]

If the party can hunt some animals quickly, they might be able to jury-rig some furs for clothing.

If you're open to third party materials, you can offer the players the 4th level spell Temperature Zone from this Artificer book on DMsGuild. If any of the PCs is a full caster, it'll probably last the party long enough to find shelter or animals to hunt.

http://www.dmsguild.com/product/204687/THE-ARTIFICER-5e-Revised

 

[jgsugden]

You're the DM. Add the spells you want to see in the game. Unless it is an AL game, You're good to add whatever you want.