In hot conditions, the body expands blood vessels close to the skin so that excess heat can be lost to the air, cooling the body.
In cold weather, these blood vessels constrict to conserve body heat. This constriction can starve extremities, such as the toes, of blood and warmth if your peripheral circulation is sluggish.
Abrupt temperature changes
The symptoms of chilblains are intensified with sudden temperature changes, for example, entering a warm house after being outside in the cold.