After Tuesday’s heat, cooler temperatures are likely into September

After a much warmer-than-normal start to the summer season in June, July and August have been much more “typical” for average temperatures across the region.

Of course, what has not been typical is the amount of acreage burned by wildfire in Washington state — now up to more than 400,000 acres. This is more acreage than has been burned in any year over the last decade, and many of the large fires began after an epic lightning event in mid-July.

Since then, aside from some heavy rains associated with some mountain thunderstorms, we’ve been quite dry. This is especially true in the lowlands of Western Washington, where Seattle-Tacoma International Airport (SEA) has yet to record any measurable rain in August.

While I don’t see a quick shift to very wet conditions, following one more very warm day Tuesday, there are signs of a subtle weather pattern shift. It’s one that could well be a hint that “fall” is not far away. After all, we’re losing more than three minutes of daylight each day, which robs the sun of three-plus minutes of warming ability daily!

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I’m forecasting highs in Seattle falling to near 70 degrees starting late this week and continuing into early next week. While this is just a few degrees below average, it could come with a few weather disturbances moving in off the Pacific. These could bring some rain chances, starting late this week with a few sprinkles or light showers, and possibly a better chance of rain around Saturday.

If rain falls, it’s unlikely to amount to much and would do little to help the wildfire situation, but the longer-range outlook into early September points to a better-than-not chance of cooler, wetter-than-normal conditions in the Northwest.

While August is summer’s “swan song,” September is usually when we start getting occasional fall-like weather moving into the region, though the more reliable “fall rain” is usually not arriving until the second half of the month.

Back to the “heat” on Tuesday: We’ll see widespread highs in the mid to upper 80s in the central and south Puget Sound with some low 90s in the hottest Cascade valleys. But that’s a one-and-done deal with milder temperatures back in the mid-70s for Wednesday.

While serious heat can still happen in September, the chances of very warm temperatures start to plummet quickly about this point on the calendar.

So it’s too early to break out the jackets and rain gear, but the “dog days” of summer really do look to be running out fast!