Warmth

Warmth is one of the two primary effects on your character, the other being Energy.
It is the equivalent of your character's health.
You lose warmth by being outside of the Truck, and regain it by being inside the truck, inside a Shopkeeper's building, or near a lit fire.
As you lose warmth, an Ice effect will slowly creep in from the edges of your screen, progressing to Vignetting shortly before your character falling over and dying. You can become temporarily immune to losing warmth by drinking Tea.