Portland officially hit 99° today (as of 5:30pm). I had been thinking we could skate through these last few weeks of the summer and avoid 100°. That could still happen if we don’t hit 100 tomorrow, but that’s what we are forecasting. Other official weather stations DID hit the century mark including Hillsboro and Troutdale. Here are the metro numbers as of 5pm
And around the KPTV viewing area…
But Summer 2025 has been quite reasonable so far, at least compared to recent summers. The average temperature is the coolest since 2020 and we’ve “only” picked up eleven 90° days; much better than the last 4 summers. An example of how much summers have warmed in Portland? Even though it’s the coolest in 4 years, it still warmer than all summers except 1985 in the stretch between 1940 and 2000! 1972 & 1992 were similar. Plop this summer down in the 1950s, 60s, 70s, 80s, or 90s and people would be remarking what a warm/hot summer it’s been…
We’ve got two more hot days ahead.
Notice the forecast highs aren’t record-setting since we’ve had some big heatwaves this time of year. Remember that 107° stood as Portland’s all-time high for about 40 years!
Unfortunately, it should turn a bit more humid too…yuck. Check out the GRAF model’s dewpoint forecast. When it gets above 60 in Portland…that’s a bit sweaty.
That’s one reason I prefer hot weather in late August and September; usually we get a very dry easterly wind with those events.
The good news? This appears to be a brief hot period; cooler than normal temps return the 2nd half of this week. Plus there’s no sign of another hot period through at least the 20th or so.
The bad news? If you don’t have air-conditioning, these next two nights will be tough and we’ll likely be close to 100° the next two days.
KEY POINTS
- Expect similar heat both Monday and Tuesday, highs in the 95-101° range again in the I-5 corridor
- Overnight lows will only drop to the upper 60s in the city, and around 60 in outlying areas these next two nights.
- Extreme heat warnings from the NWS continue through Tuesday
- Wednesday and beyond will be MUCH cooler, right now next weekend looks much more fall-like.
- PLEASE CHECK ON ELDERLY NEIGHBORS! This may be nothing like the June 2021 heatwave, but in any heatwave most deaths are among elderly folks that live alone.
- Showers in some form are possible somewhere between Thursday and Saturday, especially west of the Cascades. But don’t freak out if you have an outdoor wedding planned next Saturday/Sunday, it’s still a ways out there.
WHAT’S AHEAD
A very warm upper-level ridge (you can call it a heat dome), is centered well west of the West Coast. That 600 dm high would be a monster if it was parked right on the coastline. That sort of high could give us record-setting temps into the mid-upper 100s if it was in that position and a breezy east wind developed. Sure, it’s real hot right now, but it could have been 5-10 degrees hotter.
This heatwave is interesting in that forecast models correctly predicted a hot weather event, and our Monday forecast has hardly changed. But as we got closer, models increased the intensity of the hot atmosphere for today. At one point we expected lower 90s for today. And most models were pushing in much cooler marine air Tuesday for high temps back around 90 or cooler. The ECMWF model has been somewhat alone keeping Tuesday very hot; it appears it’ll be right this time. So what was a real marginal “heatwave” or hot event has now become something more substantial. Still, it’s nothing historic or exceptional, but plenty hot!…