Monthly Temperatures and Rainfall in Seattle
Seattle's mild winters and cool summers enable year-round outdoor activities. High temperatures in July average about 75° F (24° C), while low temperatures in winter drop below freezing an average of only 15 days per year. Seattle averages 158 days of measurable rain and 226 days of some cloud cover per year. Both most often occur in the winter and during the night. Seattle is in the direct path of the highly unstable Puget Sound Convergence Zone which makes local weather forecasting as much an art as a science. If you don't like the weather, be patient, it is likely to change soon! :-)
Seattle ranks 44th among US cities for rainfall with an average yearly rainfall of 36.2 inches (92 cm). This compares to 152 inches (386 cm) in Ketchikan, 145 inches (368 cm) in the Hoh Rain Forest (part of Olympic National Park in Washington State), 129 inches (327cm) in Hilo, 65 inches (165 cm) in Mobile, 60 inches (152 cm) in New Orleans, 58 inches (147 cm) in Miami, 49 inches (124 cm) in Atlanta, 45 inches (114 cm) in Houston, 44 inches (112 cm) in Boston, 40.3 inches (102 cm) in New York City, 39 inches (99 cm) in Washington, D.C., 34.5 inches (88 cm) in Chicago, 19.5 inches (50 cm) in San Francisco, 15 inches (38 cm) in Sequim (on the Olympic Peninsula in Washington State, 12 inches (30 cm) in Los Angeles and 4 inches (10 cm) in Las Vegas.
Check out Rainworks: Rain-Activated Art in Seattle.