Monday the last day of 80 degree weather around Seattle this year?

A sunny and warm day around 80 in Seattle on Sept. 11, 2017. It could be the final day near 80 this year. (KOMO tower camera image)

SEATTLE -- No matter how hot the summer is, there's always that one last warm day before autumn begins to take its annual grip on the weather.

Could Monday be that day?

Temperatures were set to top out near 80 degrees around the Puget Sound region, with a little cooling coming Tuesday and then highs comfortably around 70 for much of the rest of the week. Long range models suggest that next week, highs will drop to being consistently more in the 60s -- perhaps even a day in the upper 50s -- as summer runs out the clock and autumn officially takes over on the 22nd.

That's not to say that the 80s are impossible to reach in fall -- there are some record highs in the 80s into mid-October in Seattle, including an 89 degree day on Oct. 1 in 1987. The latest 80 degree day is Oct. 14 -- when it hit 80 in 1961. (The record high six days later is 69.) But with nothing close to 80 for the next two weeks and that we are losing about 3-4 minutes of daylight a day as we head toward the equinox, it's becoming more difficult by the day to get that warm.

Correspondingly, we can say with about 99 percent confidence that the 90s are done -- the latest 90 degree day on record in Seattle is September 22.

But it's not like we haven't had enough heat to last for a while. Despite a relatively tame June and July, August and early September were hot enough to challenge 2015's lofty numbers for hot days, including setting a record this year for most days at or above 85 degrees at 26, breaking 2015's record of 25. We also were way above average with 8 days at 90 or hotter -- a number that surely would have been closer to the record 12 had it not been for so many smoky days that held temperatures in the upper 80s.

So if you can sneak out of work early Monday, perhaps this is your time to do so if you need some last morsels of heat. For those of you ready for autumn, your time is coming soon!

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