In June 2021, Multnomah County, Oregon, experienced the most extreme heat event in its history. A “heat dome” settled over the county, trapping hot air in the region for nearly a week. Over three consecutive days, temperatures in Multnomah reached highs of 108 degrees Fahrenheit, then 112 degrees, and finally 116 degrees. Temperatures in inner city Portland reached 124 degrees (51.5 degrees Celsius). All of those high temperatures exceeded those of any day in any previous year in the county, ever.