Rainfall Patterns: How Washington Compares Nationally

The Hoh Rainforest is located on the western side of Washington's Olympic Peninsula. It has thousands of acres of bright green moss. Near the old logging town of Forks, this rainforest is known for receiving more rainfall than any other forest in the lower 48 states.tes.

How much rain falls in the Hoh Rainforest?

CREDIT: Sloane Kim Petersen via Facebook

An average of 129 inches of rain falls annually in the Hoh Rainforest. Almost half of the annual rainfall (60 inches) occurs in the rainy months of November, December, and January.

With as much rain as they get in the Hoh River area, you'd quickly think that Washington would be near the top for most annual rainfall in the US.

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The Puget Sound region, known for many cloudy, drizzly days, is protected by the Olympic Mountain Range. Seattle's 39.34 inches per year doesn't even come close to Forks's average annual rainfall of 129 inches. The Emerald City would easily have almost as much rain as Forks and the Hoh Rainforest area if not for the Olympic Mountains.

Why is Central/Eastern Washington so dry?

Back End of Saddle Rock in Wenatchee Foothills PHOTO CREDIT: Connor

Yet another mountain range, the Cascades, adds another layer of protection from rainfall for the eastern half of Washington.

If you’ve driven from Seattle to Central Washington, you’ve experienced starting your drive in gray, drizzly conditions. The rain and drizzle remain constant as you gain elevation to Snoqualmie Pass. Then, the rain and the clouds slowly disappear as you drive from Snoqualmie Summit to Cle Elum. Depending on the weather flow from the Pacific, the central part of Washington is protected by one, sometimes two, mountain ranges. For this reason, the towns of Wenatchee and Yakima enjoy an average of 300-plus days of sunshine and much less rain than the west side of the state.

Washington. Known for the wet side and the dry side.

You might think Washington gets a lot of rain, but it actually ranks 29th among all U.S. states for average annual rainfall. I was surprised that the Evergreen State is not even in the top half of states in terms of rainfall.

How does Washington compare to its Northwest neighbors?

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Washington’s annual rainfall, 38.4 inches, ranks 29th in America. Oregon is ranked 36th nationally—its towns see an average of 27.4 inches of rain. Idaho is the driest of the three, ranking 42nd. Montana is the driest in our region, coming in 45th, just missing America's top five driest states.