Much of the area is considered high desert, with annual rainfall of just 7 inches a year. But in winter, in the higher elevations, it is quite common to have snow on the ground from November until March. This is a decidedly four-season region, with wet, cool, windy springs, beautiful warm summer days, and gorgeous falls with colors to match those of any Northeastern state. Best time to visit is April through October, unless, of course, you're looking to ski, snowboard, or snowmobile.
The main wine-tasting season begins in late April and runs to the end of the fall harvest in November. Winery hours vary in winter, when you should call ahead before visiting. The Yakima Valley Winery Association (www.wineyakimavalley.org) publishes a map-brochure that lists wineries with tasting-room hours. Most are owned and managed by unpretentious enthusiasts, and their cellar masters are often on hand to answer questions.