Could Tuesday have been the final “hot” day of the year across Western Washington? Seattle-Tacoma International Airport (SEA) topped out at 84 degrees, Bellingham hit 83 , its warmest temperature of the month , and Everett-Paine Field surged to 88 degrees, establishing a new daily record high.
The answer to that question is probably no, as Tuesday was likely not the last warm day of the year. Still, the next 10 days, covering the Labor Day holiday weekend, are expected to bring significantly cooler conditions along with a rising chance of showers. Some wet weather may indeed arrive during a summer that has been unusually dry.
Dry summer thus far
At SEA, only a trace of rain has been recorded, with the last “significant” precipitation falling on July 16, when just over a third of an inch was measured. Before that mid-July rain, roughly a half-inch fell on June 9. Since that early June date, SEA has accumulated just over 0.4 inches of rain.
As August draws to a close, many would welcome any showers. Additional rainfall would help clear the air and provide moisture for the parched landscape.
Change in the weather pattern
On Thursday, a weak upper low pressure system off the coast is expected to move inland, delivering the first chance of showers. Any precipitation from this system will be very light and scattered at best.
Another, stronger upper-level system is forecast to move onshore Saturday, offering a better opportunity for showers. These hit-and-miss showers will likely produce only light rainfall amounts.
The next possibility of showers is anticipated on Tuesday and Wednesday of next week, providing an even better chance of more widespread and meaningful precipitation. A subsequent weather system will also bring another opportunity for showers on Friday.
High temperatures throughout this stretch of increased cloud cover and potential showers are expected to hover near average for late August into early September, ranging from the upper 60s to mid-70s. This period of weather also promises that out-of-area wildfire smoke should remain limited, resulting in good air quality.
Labor Day weekend outlook
Longer-range forecast charts for Labor Day weekend show drier conditions with some sunshine and slightly warmer temperatures. Looking back at the other summer holiday weekends , Memorial Day and the Fourth of July , Labor Day weekend appears poised to stay dry and join the other dry holiday weekends this year.
More ‘hot’ weather?
Could more “hot” days be ahead heading into September? Yes, that is quite possible. However, the odds of reaching 90 degrees or higher are shrinking. So far this year, SEA has hit 90 or better four times.
Daylight hours are growing shorter as the autumn equinox approaches on Sept. 22, less than a month away. Wednesday will mark the year’s final 8 p.m. sunset.
SEA has reached 80 degrees or higher 34 times so far this year, above the average of 26 days dating back to when records began more than 130 years ago. Yet since 2013, SEA has averaged 41 days of 80 or better, reflecting the overall warming trend during this century.
The latest outlook for all of September shows odds favoring 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. However, the odds of doing so are also diminishing.