Historic heat wave for the Pacific Northwest

Jun 25, 2021

Extreme and dangerous heat will overtake the Pacific Northwest this weekend and early next week.

Extreme and dangerous heat will overtake the Pacific Northwest this weekend and early next week. Locations in Oregon and Washington will challenge all-time record highs, with temperatures edging above 100° in Seattle, and likely over 105° in Portland. Interior locations east of the Cascade Mountains, like Spokane, will soar to near 110°.  In many cases, temperatures will be 25-30° above normal. See forecast highs from the NOAA/NWS National Digital Forecast Database.

Below are some resources to cover this historic heatwave

Current all-time records (via NOAA ACIS)

The Climate Connection

There is a strong and direct link between extreme heat and climate change. In a warming climate, extreme heat is happening more often and lasting longer. 

Quick points:

  • The weather pattern building into the Northwest is referred to as a heat dome and is associated with a blocking jetstream. The influence of climate change on blocking blocking weather patterns is an active area of research
  • Parts of the Pacific Northwest are locked in a severe to extreme drought. Dry soils heat more easily than moist soils, contributing to the higher temperatures near the ground. And as the climate warms, soils dry out more quickly, reinforcing the heat and making droughts worse


A small increase in average temperature leads to a large increase in extreme heat. Download the graphic at left.
A key indicator of a warming climate, the number of new record high temperatures is outpacing the number of record lows. Find graphics for all cities (i.e. Portland).
Our 2021 summer package contains city-specific data for the number of hot days, the average summer temperature (i.e. Seattle), and the average summer low temperatures.
The relationship between carbon dioxide and temperature is well defined. The increase is from the burning of fossil fuels, and the jump in each has been especially strong the past few decades.

Special Workshop

Watch our workshop on extreme heat from our recent Covering Disasters series: Extreme Heat 2020.


Extreme heat is the leading weather killer. This is especially true in climates that are not accustomed to it. 

  • 91 percent of American households have some type of air conditioning, the number is smaller in the Pacific Northwest — 44 percent in Seattle and 79 percent in Portland.
  • According to the CDC, an average of 702 heat-related deaths occurred in the United States annually between 2004-2018. And heat exposure and its impacts fall unequally, with historically underserved populations facing greater health threats. That disparity means that Black, Indigenous, Latinx, Asian, Pacific Islander, and multiracial populations, as well as those with lower incomes, are at heightened risk.

Experts Available for Interview

Additional resources