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Meteorologists expect Portland to sizzle this weekend, with temperatures in the high 90s and a modest but real possibility of topping 100 degrees on Monday. Sunsets will provide little relief, the National Weather Service says, with overnight temperatures expected to hover in the upper 60s.
But Multnomah County officials say they will not decide before the day the heat hits whether to open cooling shelters. Instead, the county plans to hold daily coordination calls during the heat to determine whether cooling centers should be activated later that day.
“Planning work has already begun, and if we reach thresholds, we will be ready to open,” Sarah Dean, a Multnomah County spokeswoman, told WW in a written statement.
County spokespeople emphasize that the cooling shelters have been chosen and supplied. Contractors have agreed to run the shelters, and the county has begun recruiting staff to work there over the weekend. The only decision remaining is whether to actually open—at which point, the locations will be announced.
An extreme heat watch has been expanded and is now in effect from Sunday until Tuesday due to a slight uptick in forecast temperatures as Portland prepares to see its hottest days of the year so far.
In extreme heat, Multnomah County and the city of Portland say they open cooling spaces such as daytime cooling centers and overnight shelters as needed. Cooling centers, Dean says, are opened when the county sees dangerously hot temperatures and remain open in the hottest part of the day.
Round-the-clock cooling shelters, on the other hand, are only open during “extremely severe heat events.”
The county has not opened an overnight cooling shelter since 2022.
Dean says communicating the dangers of heat is more effective than any other strategy. The county has provided information and supplies to about 850 property managers to help them deal with hot conditions in their buildings.
“A core part of our response is communication before and during an event, letting people know that heat is dangerous, how to recognize the signs of heat illness, who is most vulnerable to heat illness, and strategies to keep themselves, their families, and their neighbors safe,” Dean says. “Communication is our most effective strategy for reducing heat illness.”
Dean says the county tailors its heat response to the most at-risk members of the community based on previous heat-related deaths.
“Unlike extreme cold—when people living outside are most at risk and when shelter and housing can be the difference between life or death—extreme heat is most dangerous for housed vulnerable people who do not have air conditioning or do not run it because of cost,” Dean says.
Data from Multnomah County, Dean says, shows 13 of the 14 confirmed heat-related deaths between 2021 and 2024 were people living indoors.
The opening of cooling spaces is determined by NWS HeatRisk categories, which range from green (no risk) to magenta (extreme risk). The county considers opening cooling centers when the heat risk index is red (major risk), which Portland is expected to reach Monday.
In its most recent forecast, the National Weather Service’s Portland office expects daytime highs in the Willamette Valley to reach the 90s Sunday, Monday and Tuesday. “A factor to take into account in this forecast are also the overnight low temperatures,” a meteorologist writes. “In general, we are seeing overnight lows in the mid-60s and even near 70 degrees on Monday into Tuesday night. These temperatures will leave little to no relief overnight.”
Clackamas County announced 17 cooling centers on Thursday that residents can turn to during the heat wave, including public libraries and community centers. The county will also consider opening an overnight shelter at The Father’s Heart in Oregon City for vulnerable and unhoused populations. Decisions will be posted at 11 am each day.
Multnomah County, too, is directing people to cool indoor spaces. “Cool spaces like libraries, community centers and malls will be open and welcoming visitors during normal hours this weekend, which overlap with the hottest parts of the day,” the county said in a statement. “If someone in Portland needs help finding a cool space this weekend, they can dial 3-1-1 between 7 am and 8 pm or visit multco.us/hot for an interactive map."
This story has been updated to to more fully reflect Multnomah County’s preparations.
