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

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Sept. 1 marks start of Meteorological Fall in WA