With cooler weather inbound, was Tuesday western WA’s last hot day of the year?

Was Tuesday the last “hot” day of the year in Western Washington? Seattle-Tacoma International Airport (SEA) reached 84 degrees, Bellingham 83 (warmest of the month), and Everett-Paine Field climbed to 88 degrees, setting a new daily record high.

The answer to this question is likely not the last hot day of the year, yet the next 10 days, including the upcoming Labor Day holiday weekend, reflect much cooler weather with a growing threat of showers. Yes, some potential wet weather may be in store during a summer that has been quite dry.

Dry summer thus far

At SEA, only a trace of rain has fallen, and the last “significant” rainfall was on July 16 with just over a third of an inch of rain. Before that mid-July rain, about a half-inch fell on June 9. Since that early June date, SEA has received just over 0.4 inches of rain.

As August comes to an end, for many any showers will be welcome. Rainfall will help cleanse the air and offer some water for the thirsty landscape.

Change in the weather pattern

On Thursday, a weak upper low pressure off the coast is forecast to track inland, bringing the first threat of showers. Any showers with this weather system will be very light and spotty at best.

Another stronger upper-level weather system is due to track onshore Saturday for a better chance of showers. These hit-and-miss showers will likely provide only light rainfall.

The next possibility of showers is expected on Tuesday and Wednesday of next week, offering an even better chance of more widespread and meaningful rainfall. A following weather system will also pose another chance for showers on Friday.

High temperatures throughout this period of more clouds and the potential for showers are expected to be close to average for late August into early September, from the upper 60s to mid-70s. This period of weather also promises out-of-area wildfire smoke should remain limited, resulting in good air quality.

Labor Day weekend outlook

Longer-range weather forecast charts for Labor Day weekend show drier weather with some sunshine and a bit warmer temperatures. Reviewing weather from the other summer holiday weekends – Memorial Day and Fourth of July – Labor Day weekend looks to be dry and join the other dry holiday weekends this year.

More ‘hot’ weather?

Could more ‘hot’ days be in store heading into September? Yes, it is quite possible. Yet, the odds of reaching 90 degrees or better are shrinking. So far this year, SEA has hit 90 or better 4 times.

Daylight hours are growing shorter as the autumn equinox approaches on Sept. 22, less than a month from now. Wednesday will be the year’s final 8 p.m. sunset.

SEA has reached 80 degrees or higher now 34 times so far this year, above the average of 26 days going back to when records began over 130 years ago. But since 2013, SEA has averaged 41 days of 80 or better, reflecting the overall warming trend during this century.

The latest weather outlook for all of September shows chances in favor of warmer-than-average temperatures. Could SEA and much of the rest of western Washington reach 80 degrees or warmer in September or even October? Yes, it could happen. Yet, the odds of doing so are also dwindling.

Ted Buehner is the KIRO Newsradio meteorologist. Follow him on X and Bluesky. Read more of his stories here.