Portland is staring down the barrel of triple-digit temperatures on Independence Day weekend, with National Weather Service meteorologists now predicting a one-in-four chance of highs reaching 110 degrees by July 5.

On Monday afternoon, the NWS’ Portland office said an already hot holiday forecast had “changed dramatically” and it was more likely than not that Portland temperatures would rise above 100 degrees starting Thursday, July 4 due to an upper level ridge—that’s an elongated area with relatively high atmospheric pressure. NWS meteorologists say there’s a 25% chance that highs will crest above 110 degrees between Friday and Sunday.

“Regardless of whether high temps wind up near 100, 105, or 110, it will be more than hot enough for people to suffer from heat exhaustion or heat stroke if outdoors for a prolonged period of time,” the NWS wrote, “or for people who are indoors with no air conditioning.”

The forecast summons unpleasant memories of the 2021 heat dome that killed 72 people in the Portland metro region, as temperatures reached 116 degrees. While this heat wave isn’t expected to be as blistering, it will occur during a holiday weekend packed with outdoor activities, from soccer matches to concerts and fireworks.

WW reached out to Multnomah County for information about cooling centers, as well as organizers for large outdoor events, including the Waterfront Blues Festival and Independence Day Fireworks Show in downtown Portland, and the multi-site Pedalpalooza mass bike ride. This story will be updated as we receive their responses.

The Original Practice Shakespeare Festival has postponed this weekend’s planned productions of Merry Wives of Windsor and King Lear in Cathedral Park. Brian Saville Allard, OPSF’s artistic co-director, cited the company’s policy not to perform in temperatures above 95 degrees as a reason for rescheduling the plays, along with a new Portland Parks & Recreation policy requiring four days’ notice of an event to be rescheduled if canceled.

“[T]he rules about everything this year have been significantly more restrictive than in any of our 15 previous seasons,” Saville Allard wrote via email, saying OPSF would soon announce their new show dates.

Extreme heat can be deadly for anyone, from the unhoused to people working outdoors. Age, health history and access to cooling relief like air conditioning are all significant factors. The NWS says sidewalks will also be scorching hot to anyone touching them, human or animal.

“Walking your dog in the afternoon will not be a good idea as their paws may easily burn,” the National Weather Service added. “It’s also worth mentioning that overnight lows are looking quite warm with minimal overnight relief.”