MYNORTHWEST WEATHER

Sept. 1 marks start of Meteorological Fall in WA

Sep 2, 2025, 2:00 PM

meteorological fall...

People enjoy trees near their peak autumn foliage. (Photo: Spencer Platt, Getty Images)

(Photo: Spencer Platt, Getty Images)

Monday, Sept. 1, marked the start of Meteorological Fall. Yes, the astronomical summer season continues until the Fall Equinox, which falls on Sept. 22 this year. Yet, the meteorological fall months of September, October, and November better represent what the time of year feels like.

As another example, the months of December, January, and February mark Meteorological Winter – the coldest months of the year, while June, July, and August are the hottest months and are considered Meteorological Summer.

Astronomical Fall, commonly called the first day of fall, starts with the Fall Equinox and runs through until the Winter Solstice, the shortest day of the year, in late December. So the difference between the Astronomical and Meteorological seasons simply comes down to the start and end dates.

If it seems summers are running longer in recent years, your sense would be on target. Studies have shown that since the 1950s, the global summer season is now an average of three weeks longer, starting earlier in the spring and extending into fall. Recall in 2022, high temperatures in the Puget Sound area soared into the 80s on Oct. 16, the warmest ever for so late in the year.

Regardless, fall is just around the corner as the days get shorter, nights longer, and cooler, wetter weather returns. In the meantime, enjoy the remaining summer weather until those fall rains arrive.

Ted Buehner is the KIRO Newsradio meteorologist. You can read more of Ted’s stories here and follow him on X

MyNorthwest Weather

earthquake panama...

MyNorthwest Staff

Magnitude 7.6 earthquake strikes Panama; no tsunami threat to West Coast

A powerful magnitude 7.6 earthquake struck Panama on Friday morning, shaking buildings as far away as the capital and prompting evacuations.

1 day ago

seattle fog 70s wa...

Aaron Granillo

So long 70s, hello ‘Fogtober’

Western Washington gets one more taste of summer before cooler temperatures, light rain, and chilly nights settle in.

2 days ago

october rain weekend...

Chief Meteorologist Morgan Palmer, KIRO 7 News

October reality check on the way with weekend rain and chill

This pattern of morning gloom and afternoon sunshine won’t last. And we have just one more day with balmy highs in the mid-60s and 70s before changes sweep in.

3 days ago

70 degrees weather...

Meteorologist Nick Allard, KIRO 7 News

Weather: Say goodbye to 70 degrees

Thursday could be our last shot at 70 degrees for a while. After another mild day tomorrow, a much cooler pattern moves in on Friday with rain and gusty winds.

4 days ago

morning fog western washington...

Chief Meteorologist Morgan Palmer, KIRO 7 News

Why the morning fog won’t quit across Western Washington

The start of October days has been gray and gloomy in the lowlands of Western Washington, with morning fog and low clouds only slowly breaking in some spots through midday.

5 days ago

autumn weather seattle october...

Meteorologist Nick Allard, KIRO 7 News

Seattle begins October with dry weather following an unseasonably cool month

Seattle just wrapped up an unusually cool September, the coldest September here since 2007, with an average temperature of 60.4 degrees, more than two degrees below normal.

6 days ago

Sept. 1 marks start of Meteorological Fall in WA