Aside from the Olympic rainforests, most of the “wet side of the mountains” actually isn’t all that wet: Seattle’s annual rainfall of 38 inches is less than that of Chicago or New York. Winter snowfalls are generally light and melt quickly; a real snowstorm paralyzes the city for days due to the lack of snow-removal equipment and snow-driving expertise among natives.
Typical western Washington weather is mild and wet in the winter, warm and dry in the summer. Semipermanent high- and low-pressure systems in the North Pacific create predictable patterns of clouds and light rain beginning in October, with daytime temperatures in the 40s throughout most of the winter; December and January are the region’s wettest months. In spring, the clouds give way to partly sunny days, and it’s not unusual to have six weeks of cloudless skies in July and August. Summer daytime temperatures are usually in the 70s and 80s, with perhaps half a dozen 90°F days each year. Thunderstorms are rare, and tornadoes even more so; the humidity is low despite the area’s moisture.
Seattle averages about an inch of snow per month in winter, though many winters are snow-free. Mount Rainier is the place to go for snow—in the winter of 1955–1956, the Paradise ranger station (elev. 5,500 feet) received 1,000 inches (83 feet) of snow. Winters with at least 70 feet are the norm. Cascade ski areas usually open in November and remain open through early spring, beginning and ending with Mt. Baker’s eight-month ski season.
© Ericka Chickowski from Moon Washington, 8th edition