Daytime high temperatures are expected to top 100 degrees through mid-week in many locations across the Northwest, including typically milder areas in western Washington and Oregon.
The National Weather Service is forecasting a high temperature of 104 degrees in Portland and the Willamette Valley on Monday, 101 degrees on Tuesday and 99 on Wednesday before dropping into the low 90s by Thursday.
Portland’s daytime highs in August usually average about 80 degrees.
An excessive heat warning issued Monday by the weather service is in effect through Thursday across southwest and eastern Washington and into northern Idaho.
Temperatures from 96 to 108 are expected and pose an increased risk of heat-related illnesses for much of the population, pets and livestock, especially with extended outdoor exposure, said the weather service.
Overnight temperatures will drop to the mid-60s to low 70s, providing some limited relief.
Prolonged exposure to heat can be dangerous to anyone without proper hydration or adequate cooling, possibly heat exhaustion or heat stroke.
“For those without air conditioning, living spaces can become deadly during the afternoon and evening,” the National Weather Service said in its advisory.
Precautions include drinking plenty of fluids, staying in air-conditioned spaces and out of the sun as much as possible, starting during earlier cooler hours if working outdoors, and checking on relatives and neighbors.
Children and pets should not be left in unattended vehicles, where interiors can reach lethal temperatures within minutes.
“Stay cool, stay hydrated, stay informed,” said the weather service.
Updated information is available online at www.weather.gov and www.heat.gov.
