4. C: It depends. In cold weather, you can dehydrate quickly without knowing it. And when you are dehydrated, you are much more susceptible to the cold. You need to drink at least 2 quarts of water per day, and you must drink that water before you feel thirsty. When your mouth gets dry, you've waited too long. Carry water next to your body to keep it from getting too cold. If you have waited too long to drink, it's best to build a small fire and brew up a hot drink, which will rehydrate your body without draining body heat. If a fire is not an option, drink the water anyway.