Nearly all areas of Oregon and Southwest Washington remain under excessive heat alerts through at least Tuesday night.

The National Weather Service says temperatures are expected to peak Tuesday when highs could reach 105 degrees in the Willamette and Hood River Valleys.

Officials urge people to drink plenty of water, stay out of the sunshine, and check up on relatives and neighbors during the heat wave.

People should stay in air-conditioned spaces if possible, and can call 211 or visit 211info.org for help finding a cool place. Many counties and cities across Oregon and Southwest Washington have opened cooling centers to help people beat the heat.

Temperatures west of the Cascades are expected to drop into the low-90s by Wednesday. Temperatures in central and northeastern Oregon could stay between 95 and 100 degrees through next weekend.

Related: Gov. Tina Kotek declares statewide emergency as heat wave hits Oregon

From the 1930s through 2020, Portland and Eugene averaged about one day above 100 degrees per year, with occasional heat waves that lasted longer. In 1944, Portland’s airport reported five consecutive triple-digit days.

But high summer heat has become more routine over the past four years, with summer temperatures climbing about 3 degrees on average since 2020, an indicator of human-caused climate change that climatologists have predicted for decades.