
SEATTLE — Winter solstice is still three weeks away, but the season is already underway in a meteorological sense.
Differing from astronomical seasons, meteorologists and climatologists measure them in three-month cycles, based on typical temperature patterns.
As the National Oceanic and Atmospheric Administration explains:
“We generally think of winter as the coldest time of the year and summer as the warmest time of the year, with spring and fall being the transition seasons, and that is what the meteorological seasons are based on. Meteorological spring in the Northern Hemisphere includes March, April, and May; meteorological summer includes June, July, and August; meteorological fall includes September, October, and November; and meteorological winter includes December, January, and February.”
If the last few months have felt unusually wet, it’s not your imagination. As Puget Sound closed the books on meteorological fall Tuesday, Puget Sound set a new all-time record for precipitation. Seattle logged more than 19 inches of rain between September and November. Seasonal totals were even more eye-popping elsewhere in the state.
Seattle’s new meteorological fall rain record is impressive in its own right, but pales in comparison to what fell in 90 days over parts of the Olympics & Cascades with more than 50 inches. In Forks, rain in the past 90 days exceeds what Vegas typically gets in 13 years.#wawx pic.twitter.com/42uOdfh1XB
— NWS Seattle (@NWSSeattle) November 30, 2021
November is typically the wettest month of the year for Western Washington, and this one was no exception, landing among the top five wettest since 1945 and contributing more than half of the three-month precipitation total in just 30 days.
Rainfall for meteorological fall in Seattle has surpassed 19″ – a new record. Contributions by month this year: Sept. 15.9% Oct. 30.3% Nov. 53.8% Contributions by month in prev. record (18.61″ in 2006): Sept. 7.7% Oct. 8.3% Nov. 84% Novembers wet reputation lives on. #wawx
— NWS Seattle (@NWSSeattle) November 30, 2021
Looking forward to a ‘double-dip’ La Niña winter
The wetter trend could carry on through the colder months to come, as Western Washington enters its second La Niña winter in a row. Earlier climate forecasts remained on track in November, with the odds continuing to favor a cooler and wetter winter in the Pacific Northwest.
In an update shared in late November, NOAA’s climate office walked through the latest probabilities, accounting for the relative uncertainty over how no two La Niñas behave exactly the same.
According to NOAA, the phenomenon’s influence tends to have more consistent impacts on precipitation, while playing a less reliable role with temperatures. This year, Washington looks to have a slightly better shot at a wetter-than-normal season, with the probabilities slightly lower on the temperate front.

“Probabilities are tiled toward colder-than-normal temperatures along the northern tier from the Pacific Northwest to the Dakotas and across much of Alaska,” wrote Mike Halpert, deputy director of the Climate Prediction Center. “However, the probabilities for below average in these regions are less confident, with none reaching 50%.”
As the Seattle Weather Blog noted Monday, some — but not all — of Washington’s rainiest Novembers heralded snowy winters to come.
Snowfall-wise, 3 of the top 4 wettest Novembers were followed by decent snows in winter (2006, 1995 & 1990). 1998 was a downer, with only about 2″
— Seattle Weather Blog (@KSeattleWeather) November 29, 2021
Federal climatologists update their seasonal probabilities each month, and the next one is due by mid-December.
Source: Bellevue Patch
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