It's common to get the munchies when the temperature drops. Eating is one way that your body warms itself. So if you're exposed to colder weather (even if only for a few minutes), your core temperature begins to drop, thus triggering your appetite.
This doesn't necessarily mean you need more food. If you start shivering, by all means grab a snack. (Shivering can burn up to 400 calories an hour.) But for those who enjoy exercising outside, this is one way to give your calorie burn a boost. Your body burns up to 13 percent more calories in colder conditions. For instance, if you burn 500 calories during your morning run in the spring, you can expect to burn about an additional 65 calories in the cold.
To quell your cravings during chilly workouts, dress warmly, spread your meals throughout the day, and eat before and after your workout. If you feel hungrier than usual after your workout, add an extra piece of fruit or half an energy bar to your post-workout snack.