For coping with extremes in general I thoroughly recommend siberian ginseng. It is an adaptogenic herb, which means it helps your body adapt to changes, whether it is changes in temperature or some other physical change. The russians used to give it to their cosmonauts and olympic athletes.
Coconut oil is very warming, it increases basal body temperature. If you are taking at theraputic dosage (i.e. 2-3 tablespoons a day) you should notice its effect pretty soon.