Big Bend National Park is a generally dry place with low humidity. The rainy season from June to October includes heavy thunderstorms and some flash flooding. Things dry out quickly in the arid climate. Fall and spring are usually warm and pleasant. Summers are hot, although temperatures vary greatly between the desert floor and the Chisos Mountains; May and June are the hottest months. Winters are generally mild, although periods of cold weather, including light snow, are possible.