Is the Hottest Weather of the Year Behind Us?

It's been a warm, sunny summer in Seattle--with just one significant hot spell in late June.

For the past three years, we’ve notched our hottest temperature of the year in August.

But this time around, barring an unlikely late-summer scorcher, it’s June that will wind up home to the year’s warmest reading.

Seattle hit 93 degrees on June 30 at the height of an early-season heat wave—the only time the city has cracked the 90s all summer. While we’ve certainly seen a slew of warm weather since then—July finished 2.3 degrees above normal, and temperatures this month are currently running 2.7 degrees on the plus-side of average—truly hot conditions have escaped us. And now, with summer in its final month, the window of opportunity for a day in late August or September to one-up June 30’s mark is rapidly shrinking.

Since record-keeping began at Sea-Tac in 1948, only three days later than today have risen above 93 degrees. The first instance was on Aug. 28, 1967—at the tail end of Seattle’s warmest month on record—when the mercury spiked to 95. Time number two came on Sept. 7, 1981, when the airport topped out at 94. The third—and hottest of the bunch—fell at the start of Labor Day weekend in 1988, when the mercury soared to an incredible 98 degrees on Friday, Sept. 2. (Not only is this Seattle’s hottest temperature ever recorded in September, it’s also tied for the sixth-warmest day on record at Sea-Tac.)

Notably, we’ve never reached beyond 93 degrees after the first week of September—so any challengers out there hoping to give June 30 a run for its money have just over two weeks to show up before they’re fighting history. We have, at the least, managed to hit exactly 93 twice from here on out—once on Sept. 15, 1967, and again on Sept. 14, 1979—so theoretically, there’s still three-plus weeks remaining for a tie.

At this point, there’s no extreme heat on the horizon—although long range forecasts do call for above normal temperatures to close out August. In the here-and-now, our trend of warm—but not hot—weather will continue through tomorrow, with highs rising into the mid 80s. Sunny skies will hold through tomorrow evening, before a shift in winds floods the region with marine air on Friday. With cloudy skies throughout, temperatures on Friday should tumble back into the mid 70s.

The cooler conditions continue into the weekend under a mix of clouds and sun—with even some isolated showers near the Cascade foothills. The culprit? Low pressure in the upper reaches of the atmosphere, which will cut off the ridge of high pressure responsible for the warm, sunny weather of late. A broad swath of low pressure will remain nearby through Tuesday, keeping our highs in check amid a slight chance of showers.

In other words, any late-blooming heat waves trying to seize the crown from June 30 are at least a week out.

Tick, tock …

2 COMMENTS

  1. What’s the record number of days over 80 in Seattle? I know that we’re probably nowhere near that this year but I was just curious to see where we stand. I figure we’ll most likely reach 40 or so by the end of September. Thanks

    • Hi Matt,

      The record is 47 from 1958–we’re currently at 33 days right now. I think you’re right–we’ll tack on several more in the final month of summer (probably 2 or even 3 this weekend), but ultimately fall short of the all-time mark. Something to definitely keep an eye on though.

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