Weather patterns across Washington state in the Pacific Northwest region are incredibly diverse. The climate is humid and temperate on the west side of the Cascade Range. On the east side, it is drier, with hot summers and cold, snowy winters. The weather within each side of the waterfalls also varies considerably, particularly when it comes to wind and precipitation.
Different areas of Washington state
Eastern Washington
Much of the land east of the Cascade Mountains is arid, be it a high desert or a pine forest. While irrigation has allowed eastern Washington state to become one of the most fertile growing regions in the world, the region’s natural foliage includes a large amount of mugwort. Cities east of the mountains benefit from the rain shadow effect, which blocks rain-producing weather systems and allows for more sunny days. As you head east, the impact of the rain shadow lessens: the city of Spokane, on the Idaho border, receives twice as much annual rainfall as Ellensburg, a city east of the Cascades.
The reverse tends to be true when it comes to snowfall in eastern Washington, where regions closer to the mountains or at higher elevations receive much more snow.
Western washington
The topography and large bodies of water create incredibly varied and often dynamic weather conditions in the western section of Washington State. The topography of western Washington is quite complex, with the relatively young Olympic Range occupying the Olympic Peninsula. Sea-level cities along the eastern side of Puget Sound make a rapid transition to the foothills of the Cascade Range, which runs the entire north-south length of the state. The Pacific Ocean, which extends to the more sheltered Puget Sound, moderates the temperature and adds humidity to the local climate.
Rain tends to squeeze out of the clouds on the west side of the Olympic and Cascade Mountains. Cities west and southwest of the Olympic Range, such as Forks and Quinault, are among the rainiest in the United States. The cities on the east and northeast side of the Olympics are in the shadow of the rain and consequently are among the sunniest and driest places in western Washington.
The most populated area, stretching from Olympia to Bellingham along the east side of Puget Sound, is also affected by varied weather conditions. Whidbey Island and Bellingham, which face the Strait of Juan de Fuca, tend to be much windier than most of western Washington state. The Olympic Mountain Range divides the flow of air coming out of the Pacific Ocean. The point where the flow converges again, typically in the North Seattle to Everett area, tends to have extremely dynamic weather that can vary significantly from a few miles to the south.
This region is called the “convergence zone,” a term you’ll often hear in western Washington weather forecasts.
Spring in Washington State
Spring in Washington State means different things in different areas. In the western part of the state, temperatures rise and there is less rain. However, the rainy season continues until mid-June. Also, light snow is still possible in some areas as late as March. If you’re along the coast, spring temperatures can feel quite chilly due to the ocean breeze. In general, the coastal places will be great. March is also the beginning of the whale watching season.
What to pack: Spring weather is variable and unpredictable. You should pack plenty of layers that will keep you warm and dry in the event of rain or a late snowfall. Even the warmest spring days can have cool afternoons.
Summer in Washington State
By June, Washington’s weather begins to improve, as temperatures rise to 60 degrees (20 C). Rain is not a factor during the summer months, averaging just 1.2 inches per month during the summer. Most days are warm and sunny.
The climate is perfect for the many outdoor activities the state has to offer, ranging from hiking and fishing to just sightseeing. The western side of the Cascade Mountains has incredible natural beauty with abundant lush vegetation and other natural attractions.
What to pack : Washington is rarely so hot that a lightweight pair of pants will be uncomfortable, so you can pack to your own comfort level during the summer months. Some days will still be quite cold, so it is good to bring a jacket or sweater (hoodies are popular too).
Fall in Washington state
The good weather continues into fall – Visitors who enjoy the great outdoors should take advantage of and enjoy the fantastic hiking, biking, and boating that Washington has to offer. Fall temperatures are similar to summer temperatures, but it has the added natural beauty of the changing seasons. Contrary to what most visitors believe, early fall is mostly sunny and dry; Average rainfall in September is less than two inches. By October, temperatures drop slightly, averaging around 50 degrees Fahrenheit (10 C) and rainfall increases significantly (to six inches) in November.
What to pack : While the temperatures don’t feel cold yet, the chances of getting wet are pretty high, so pack accordingly. A waterproof jacket for the rain is essential, as well as suitable shoes that will keep your feet dry. (Leave the tennis shoes at home!)
Winter in Washington State
The rains increase throughout the fall, a trend that continues into winter. Temperatures are generally quite cold, ranging from 23 to 41 degrees Fahrenheit (-5 C to 5 C) in most of the state. While Washington receives snow, most of the state’s rainfall comes in the form of showers or drizzle. In the mountains, the ski season begins in late November and runs through April, or even May.
What to pack: During winter, you will undoubtedly experience cold temperatures and rain, so be prepared. Pack a waterproof or water resistant winter coat and shoes that can withstand the rain. You’ll also want winter accessories, like a warm scarf, gloves, and a hat.
