In addition to the air temperature, also consider the wind when dressing for cold-weather workouts and wear a wind-resistant outer layer if necessary. Cyclists often get themselves into trouble on cold and windy days when they do out-and-back rides in which they have a tailwind in the first half and generate a lot of sweat, then face a headwind on the way back, which rapidly pulls all that sweat off their bodies and chills them. You can avoid this problem by packing a wind-resistant jacket to put on at your turnaround point.
3. Don't forget to hydrate.
Athletes who routinely use water or a sports drink while training in the summer heat are much less likely to do so in the colder months. There is a tendency to assume that hydration is not an important issue in cold-weather exercise. But in reality it is just as important. Failure to drink carries the same risks in the cold as it does in the heat: dehydration, bonking, and even fatigue-related injury.
Several factors increase the likelihood of dehydration in the cold. First, cold air tends to be very dry, especially at higher altitude, and in dry air more fluid is lost as vapor through breathing. Second, the cold tends to suppress thirst so that athletes drink less even when fluid is available. Third, cold-induced dieresis causes rapid fluid loss via urination, which often reduces the amount of fluid athletes voluntarily chose to drink when exercising in the cold.
To avoid dehydration in your winter workouts, drink water or a sports drink during all workouts lasting longer than an hour, even on the coldest days. Compensate for your reduced desire to drink by drinking on a schedule of four to six ounces every 10 to 15 minutes. Sports drinks are generally preferable to water because unlike water they replace the electrolyte minerals lost in sweat and provide carbohydrate energy, plus they are more palatable. Consider heating your sports drink before you head outdoors to make it even more palatable.
Sign up for your next race.