Seattle summers are almost 3°F warmer than in 1970
Add Axios as your preferred source to
see more of our stories on Google.


Wednesday's somewhat mild weather on the first day of summer may not make Seattleites feel like they're in for a hot one. Yet temperature data shows Seattle summers have trended warmer over the past 50 years.
Driving the news: The city's average summer temperatures increased by almost 3°F between 1970 and 2022, per a new analysis by climate research group Climate Central.
Zoom in: Average temperatures in Seattle from June 1 to Aug. 31 were 66.7°F in 2022, compared to 64°F in 1970.
- That made last summer the seventh hottest on record locally.
Why it matters: Extreme heat is a serious health risk, leading to both immediate acute effects (such as exhaustion and heat stroke) as well as longer-term complications due to reduced air quality.
- A particularly deadly "heat dome" phenomenon in 2021 was linked to dozens of deaths across the Pacific Northwest, including more than 30 deaths in King County, lending fresh urgency to the problem of rising city temperatures.
The big picture: Nationwide between 1970 and 2022, summer temperatures rose by 2.4°F on average across nearly 230 locations — 95% of the locations Climate Central analyzed.
What's happening: Cities nationwide are hiring "chief heat officers" to head up efforts to mitigate urban heat, as Jennifer A. Kingson has reported, including through the use of "smart surfaces" and increasing tree cover (and thus shade).
- Seattle hired its first chief resilience officer — a position with responsibilities that include preparing for heat waves — in 2017.
Plus: For the past year, King County has been developing its first extreme heat mitigation strategy with a focus on areas that are heavily paved, something that keeps those places from cooling down as much at night.
- These "urban heat islands" tend to be more common in low-income neighborhoods, making them a key socioeconomic issue for cities to tackle.
What's next: Seattle city officials hope their efforts to boost the city's tree canopy will help cool down some of the city's neighborhoods.
- The parks department is also working to add air conditioning to community centers in neighborhoods most impacted by heat, according to the mayor's office.


