Summers Are Hotter And Longer In Washington, Analysis Shows

WASHINGTON — It doesn’t just feel as if summers are longer and hotter than they used to be in Pacific Northwest. Federal climate data, assembled in a new study by the nonprofit research group Climate Central, backs that up.

We’re less than three weeks into summer 2022, but much of the country has already experienced hotter-than-normal temperatures, according to the private weather company AccuWeather. Puget Sound has fared better, rolling its cool spring into a mild start to the season, apart from a quick brush with the 90s in late June.

That's a lot different than the same time last year, when a "heat dome" event pushed Seattle beyond 100 degrees on three consecutive days, doubling the number of triple-digit days on record for the Emerald City. This year, climate outlooks tilt the odds in favor of Western Washington staying cooler than usual through July, but many states may not be so lucky.

On average, temperatures in the Western region, which includes Washington, Oregon, Idaho, Montana, California, Nevada, Utah, and Arizona, increased by 2.7 degrees Fahrenheit from 2017-2021, compared to from 1971-2000, according to the Climate Central study, The Washington Post reported.

The outlook going forward isn’t good. Overall, federal agencies project more dangerously hot days, a worsening of drought conditions, more wildfires and more hurricanes. The effects of climate change are most sharply felt in the West.

Reno, Nev., where summer temperatures have increased 10.9 degrees F., on average, since 1970, is the fastest-warming city in the country during the hottest months, according to the Climate Central study.

The increasing temperatures can cause heat emergencies that increase hospitalizations. Heat-related illnesses are among the deadliest weather-related illnesses in the United States.

Geographic tolerance for heat is among the factors considered by researchers studying heat-related hospitalizations for a 2019 study. They found heat-related hospitalizations begin at lower heat indices in cooler regions than in the South and Southeast.

For example, heat-related hospitalizations begin with heat indices around 105 degrees F. in Texas, but 81 degrees F. in the Pacific Northwest. According to Climate Central, the greater Seattle area can expect at least three days of "extreme heat" — that is, days with a heat index of 90 degrees F. or hotter.

When it’s that hot, the risk of heat-related illnesses such as heat stroke, muscle cramps or heat exhaustion increases, according to the National Oceanic and Atmospheric Administration. The Climate Central analysis found the 25 cities with the biggest increase in dangerously hot days are found in Texas and the Southeast. All of those cities are seeing two additional weeks of extremely hot days, compared to 1970.

Following last year's deadly heat wave in the Pacific Northwest, state and county leaders have worked to stand up new measures, including an "extreme heat mitigation strategy" announced last month in King County, and new state labor rules mandating stronger protections for outdoor workers.

Climate Central looked at historic data from 246 U.S. locations to calculate the increase in extremely hot days from 1970-2021. The analysis found:

• Since 1970, 74 percent (184) reported more extremely hot days annually.
• About 51 percent (126) had at least seven additional extremely hot days annually.
• The largest change was in Austin, Texas, with 43 additional days above 100 degrees F.