How cold does it have to be to get frostbite?

Answer 1

Cold enough to Freeze and kill the cells so around 0 degrees.

However, if the skin is damp, and especially if there is wind, frostbite can occur at slightly higher temps. This is due to several factors:

1) Moisture evaporating from skin pulls additional heat from the surface. This is why sweating cools you, but it can be a liability in cool conditions.

2) Air movement increases heat loss, both directly (by moving the layer of warmer air next to your skin away more quickly) and indirectly (by increasing the rate of evaporation of any moisture on exposed skin).

3) The human body's built-in reaction to cold conditions (any time core temperature starts to drop) is to constrict blood flow to the extremities to maintain core temperature for as long as possible. Thus, your body's natural reaction may prevent hypothermia, but make you more vulnerable to frostbite.

Put another way:

The ambient temperature does NOT have to be at or below freezing (32F or 0C) for frostbite to occur. If you are wet, the wind is blowing, and you have inadequate clothing, you can still suffer frostbite and/or hypothermia even in temperatures that are technically above freezing.

Even lower ambient temperatures do make it easier to get frostbite, however.