Seattle finishes Top 10 driest ‘water’ year on record

Happy October! We start planning those pumpkin patch trips, marvel at the changing leaves, and deciding which Halloween candy would we want to finish ourselves if it’s leftover after trick or treating. (Trick question: The answer is always peanut butter cups…)

But better than pumpkins, candy and pretty trees, IT’S THE OFFICIAL START OF THE RAINY SEASON IN SEATTLE!

(Can I get a “WOO!!!”? I know there’s quite a few of you who just said it in your head. Or out loud. Or texted it in all caps to someone. If so, can we be friends? The person you just texted it to might now be having second thoughts about your friendship.)

For meteorologists, the start of the rainy season on October 1 is another fun day we get to reset stats. Today marks the start of the new “water” year in Seattle — since our rainy season of October-March splits the start of the calendar year, we also track annual rain from Oct. 1-Sept. 30 to better get an idea of how a fall-winter wet season went instead of starting the count over in the middle (though we do track traditional Jan. 1-Dec. 31 rainfall too)

This past water year qualifies as simply: Nuh-uh — at least at Sea-Tac.

Seattle finished with 29.67 inches this year – the 8th-driest on record at Sea-Tac (going back to 1945). That’s nearly 10 inches below average of 39.34 inches, and more than 6 inches behind last year.  That fell on 137 days of measurable rain, so when they say rain 9 months of the year here, you can say, no, it’s about 4 and half — if you smushed it together into one rain streak.

If you want to use Seattle’s long-time record which is currently measured at the NWS office in Sand Point neighborhood of North Seattle, but has the old Downtown data mixed in, it’s a bit better: 32.69 inches which ranks 49th driest out of 127 years of data. Probably saved a bit by the Convergence Zone.

FREE…. FREE-FALLING…

October also marks the increasing sprint head-first into much cooler temperatures. If if feels like it takes forever for spring to turn to summer, but takes about an hour and half to go from summer to autumn, you’re (mostly) right.

Here are the average high temperatures on certain dates in Seattle as we race from summer to fall, and I put in parenthesis when we hit that average temperature in the spring and summer on the warming side:

Sept. 1: 75.4 (July 5) (13 days)

Sept. 15: 72.1 (June 22) (29 days)

Oct. 1 : 66.2 (May 14) (22 days)

Oct. 15: 60.6 (April 22) (29 days)

Nov. 1: 55.4 (March 24)

So what takes nearly a month in spring to warm up to many of those average temps just takes about 2 weeks to cool down in autumn. Another fun way to look at it is the average high today on October 1 is 66.2 degrees. The *record* high on October 20th is 69.

It’s also only 107 days from our driest day of the year (August 4 — 8 times with rain since 1894) to our wettest (November 19th: 95 days with rain in past 131 years.)

So find that cozy book, make sure you’re stocked up on warm drinks, and maybe give that friend a call to explain that strange text.