What is the climate of Columbia Plateau?

The Columbia Plateau of the Northwestern United States has temperate continental climate, with hot, dry summers and cool, wet winters. Average January temperatures range from 25 to 30 °F (−4 to −1 °C), while average July temperatures range from 65 to 70 °F (18 to 21 °C). Annual precipitation ranges from 10 to 20 inches (25 to 50 cm), most of which falls in the winter months. The Cascade Range to the west of the plateau acts as a barrier to Pacific Ocean air masses, blocking much of the moisture from reaching the plateau. As a result, the climate of the Columbia Plateau is much drier than that of the western slopes of the Cascade Range.