A point of Ice Protection adds 1 point to your Armor Protection for each point of Cold on the local Scales. 3 adds 3 points, for example. However, since Heat is effectively negative Cold, 3 subtracts 3 points.

Do you want to put points on someone? Give them an Ice Aegis, or a Rime Hauberk; or both! Temperature is one of those scales that can be abruptly tipped by "province attack rituals", however, such as Breath of the Desert.