PORTLAND, Ore. (KOIN) – Time for a flashback: This time last year, we were in the middle of our heat dome at this time.

We had already set our first all-time record for Portland and many other locations and were on our way to two more days of extreme and dangerous heat. It’s a timeline that we won’t forget and an experience that was draining. It’s a memory now that is hard to believe, yet, simple to conjure up and sharply recall.


June 27 and June 28 both started warm. Morning temperatures in the 70s, into the 80s shortly after breakfast. By lunchtime, temperatures were well into the 90s. On both days, reaching 110 by 3 p.m., not cooling down below 80 degrees by midnight. It was a very small window for temperatures to drop below 80-degrees.

Through the course of the heat dome, when it was all said and done, had spent around 24 hours at or above 100-degrees.

Between June 27 and June 28, Portland had spent 18 hours in the triple-digit heat.

This was extremely pressing to our lifestyle, infrastructure, landscape, and for some, even survival. Extreme heat is the leading reason for weather-related deaths in the United States, according to NOAA.

June 27.2021 Extreme Heat Hours – Nearly 9 hours of triple-digit heat.

The heat dome expanded across the PNW for five days. Two days above 90 degrees, with three days above 100 degrees. The historic event was most stressful from June 26-28.

Excessive heat pushed Oregon, Washington, and portions of Canada well beyond a threshold that would be considered normal for a summer day. Afternoon temperatures were 30 to 38 degrees above average. The positioning of that high pressure allowed for an east wind to come cranking down the mountains.

The combination of the east wind, sunshine, and anomalous high pressure, created the sweltering conditions for the PNW.

Weather pattern over the PNW June 28,2021 – Heat Dome

Just how sweltering? Temperatures across the Willamette Valley topped off well into the triple-digits.

All-time record high temperatures after heat wave June 28, 2021

Most beat out all-time record high temperatures between 5 to 10 degrees. Salem hit 117 degrees on Monday, June 28, while the Portland airport hit 116 degrees.