Northwest Washington Weather
and San Juan Island Rain

A contented San Juan Island slug

The spectre of Northwest Washington weather, even rain on San Juan Island, has grown to mythical proportions. It is an urban legend that has even made its way into the movies. Remember the movie, "Sleepless in Seattle," when Dennis (David Hyde Pierce) is talking to his sister, Annie (Meg Ryan), about what a bad idea it would be to move to Seattle since "... it rains nine months out of the year in Seattle."?

While it is true that the northwest has a temperate climate which includes more rain than snow during fall and winter, the myth has gained momentum and is now pretty far out of whack. Looking at the annual rainfall in major U.S. cities and you might be surprised to see that Seattle is not even in the top 10. According to, Louisiana gets the most rain (about 60" per year) followed by Alabama (57"), Alaska (53"), and Mississippi (52"). Believe it or not, Washington state (27") gets even less rain than Kansas (28")!

Sounds nice, but the numbers can be misleading. Even though the total amount of rainfall is less than other areas of the world, the rain that does fall comes down mostly in very small amounts, sometimes like mist. It is spread thinly over a wide range of days, which naturally translates to more grey, drizzly weather. That's why Northwest weather is famous.

In any case, though, since San Juan Island is in the rain shadow of the Olympic mountain range, we get far less rain than Seattle, only a couple hours to the south. Rain clouds dump most of the rain on the mountains (and over the Seattle area) so that there simply isn't as much left to fall on the Islands.

Here are the numbers: Friday Harbor annual rainfall is around 28", with Seattle at 38" (from Look up more global weather.

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