It is so important to be well hydrated and to dress properly and hydrate when the weather becomes colder.
I discuss the importance of proper hydration in the safety posts and provide a couple of good resources for further information.
This video discussed my advice for dressing properly when the weather turns colder. Although I do not recommend it, as a competitive racewalker I walk in all type of weather: warm, cold, rain, shine… wearing the appropriate gear is critical.