The Mojave is a desert of temperature extremes and two distinct seasons. Winter months bring comfortable daytime temperatures, which occasionally drop to around on valley floors, and below at the highest elevations. Storms moving from the Pacific Northwest can bring rain and in some places even snow. More often, the rain shadow created by the Sierra Nevada as well as mountain ranges within the desert such as the Spring Mountains, bring only clouds and wind. In longer periods between storm systems, winter temperatures in valleys can approach .