PORTLAND, Ore. — The forecast for Portland shows no signs of letting up for the weekend, with temperatures expected to be at or near triple digits. It's been a long week of heat for Oregon's largest city, one that could challenge a record for the number of consecutive days to reach or exceed 90 degrees, according to KGW meteorologist Rod Hill.
The longest stretch of days with 90-degree-plus temperatures recorded at Portland International Airport (PDX) is 10, set in 2009. While Portland is unlikely to break that record, the forecast indicates that this year's heat wave will tie for the third-longest stretch of 90-degree days in recorded history with eight.
"Portland's consecutive-day run of 90-degree-plus heat will likely end Sunday," Hill said. "Assuming Monday's temperature at PDX holds in the 80s, this current heat wave will go in the books as eight days in length, tying for the third-longest stretch of hot days since records began at PDX.
"It's worth noting that Portland heat waves typically last three to five days," Hill said. "Having a sixth straight day of 90-degree heat is somewhat unusual."
Hill said this week has felt even hotter because of unusually high humidity levels that have pushed the heat index higher than the temperatures.
"Making this current run of hot weather also unusual has been the high dew points near 60 degrees, which means increased water vapor and higher humidity than our hot weather typically comes with," Hill said. "Portland often sees hot weather accompanied with a dry east wind that produces hot air temperatures, but near desert-dry humidity levels. Thursday's high temperature of 96 degrees at PDX came with 40% humidity levels and a heat index of 99 degrees."
The hottest day of this current stretch of high temperatures was Tuesday, when PDX reported a record high for the date of 102 degrees. Hill said that as humidity levels lower some Saturday, the sunshine will have a better chance to warm air temperatures, which could lead to another 100-degree day.
Hill said the deadly heat wave in June 2021 saw 90-degree-plus temperatures for five consecutive days, including three straight days with temperatures above 100 degrees, including the all-time temperature record of 116 degrees for Portland.