Fifteen hours after the autumn equinox, the first fall cold front swept through Washington on Thursday morning, kicking the high humidity out of town. Now, cool, refreshing air is pouring into the region, and we can safely say summer is in the rearview mirror.

Though some subscribe to set seasons based on Earth’s position relative to the sun, the Capital Weather Gang has made a tradition of declaring the end of summer in the Washington region using meteorological criteria. When we no longer see any possibility of a heat wave or three straight days of 90-degree weather, fall has arrived. This year, we’ve passed that point.

It’s time for pumpkins, sweaters, jeans and apple-picking.

In fact, for record-keeping purposes, while we’re declaring summer over now, our last realistic opportunity for a heat wave was over a week ago when highs were 90, 89 and 90 degrees on Sept. 13, 14 and 15. So, applying our criteria retroactively, summer expired here Sept. 16.

Looking ahead, highs most days over the next two weeks are predicted to be in the 70s. While we could have a couple of days near or a little above 80 early next week, there’s hardly any chance of hitting 90 again.

Our readers seem rather enthused by the onset of fall, most responding favorably to a poem from Capital Weather Gang’s Kasha Patel announcing the equinox on Twitter:

“My favorite time of the year, specially at the Capital Crescent Trail and other parks in the DC area!,” tweeted @floharthcarter.

“Love it,” tweeted @gvukovic.

Not everyone was thrilled, however.

“Here we go: pounds of extra clothing, plenty of cloudy days and no light outside after 4 p.m.... lovely!!!,” tweeted @Machadopr78.

Our declaration of the end of summer doesn’t mean we can’t or won’t see summery days over the coming weeks. Highs in the 80s are not uncommon well into October. It just means, on balance, autumn-like weather will prevail and long-duration spells of heat are history.

Last year, summer weather ended around the same time; we declared the season over on Sept. 18.

Summer has actually held on significantly longer in several previous years. 2019 saw the mercury reach 98 degrees on Oct. 2, Washington’s highest temperature recorded so late in the year. In 2018, we didn’t declare summer over until Oct. 12. Nine of the first 11 days were above 80 degrees, and it hit 90 on Oct. 4. Summer also took a long time to depart in 2016, until Sept. 26. That September hit 90 degrees seven times, including 98 on Sept. 8.

This past summer will be remembered for rather tolerable weather in June and the first half of July. While we had our share of hot days, we also saw numerous enjoyable reprieves from the muggy weather. By the second half of July and August, though, humid heat became more persistent and we piled up the 90-degree days. It was the ninth-warmest August on record.

As of today, we’ve racked up 48 days at or above 90 degrees, which is eight above the recent average. But we shouldn’t see any more.