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The Spokesman-Review Newspaper
Spokane, Washington  Est. May 19, 1883

Weathercatch: Why Washington’s hottest temperature had to be verified (and, yes, it was right)

In this June 29, 2021, photo, Cora Richardson cools off in the Rotary Fountain at Riverfront Park in downtown Spokane. Richardson noted that the water was the perfect temperature. According to the National Weather Service that day, Spokane experienced its hottest day on record as temperatures reached 109 degrees, breaking a previous high of 108 degrees set in 1964.  (Tyler Tjomsland/The Spokesman-Review)
By Nic Loyd and Linda Weiford For The Spokesman-Review

The past five days have marked the hottest week of 2022, as did the same period in 2021. But there’s one huge difference – the intensity and magnitude of the heat that roasted the Pacific Northwest last year.

In fact, Wednesday was the one-year anniversary of the hottest day ever recorded in Spokane and in Washington state. On June 29, 2021, the mercury in Spokane surged to 109 degrees amid the unprecedented heatwave that lasted from June 26-30. Besides Spokane, record-setting temperatures were marked in Omak, where the high reached 117 degrees; Walla Walla, 116; Moses Lake, 114; Yakima, 113; and Pullman, 106.

But the most astonishing heat occurred northwest of the Tri-Cities at the decommissioned Hanford Nuclear Site. The 120-degree reading recorded that day became the hottest temperature in Washington state history, surpassing the state’s previous record high of 118 degrees set in Wahluke in July 1928 and at Ice Harbor Dam in August 1961.

The 120-degree reading, taken at the Hanford meteorological station by the Department of Energy, made big news. Even so, the National Weather Service cautioned that it was preliminary and would have to be verified.

Why’s that? It’s about science, not bragging rights. So whenever an extreme weather record is broken – whether in temperature, wind speed, snowfall amounts or even the diameter of a large hail stone, the United States has a system in place to confirm its accuracy. Formed in 2006, the National Climate Extremes Committee examines everything from satellite imagery to the weather station’s instrument sensors and surrounding terrain.

This formal review by a group of experts ensures accurate snapshots of the nation’s weather extremes and helps monitor climate changes over time, according to the National Oceanic and Atmospheric Administration. Among other things, the group aims to rule out human and instrument error, and to scrutinize the station’s location. After all, a nearby parking lot or building gives off heat that can artificially elevate temperature readings a notch or two. Also, old technologies or worn-out instrumentation can affect measurements.

Eight months after Hanford’s 120-degree reading, the ad-hoc committee of meteorologists and climatologists officially confirmed it as the new state heat record. Which, fortunately for us, will be a tough record to beat.

The Inland Northwest broke 90 degrees on Monday. Another 20 degrees hotter would be required to meet Spokane’s all-time record high of 109 set a year ago Wednesday. And to tie the state’s record of 120, we’d need another 30 degrees.

Hard to imagine the weather being that hot, isn’t it? If a weather station gets that kind of reading again, science, not bragging, will prove – or disprove – its accuracy.

Nic Loyd is a meteorologist in Washington state. Linda Weiford is a writer in Moscow, Idaho, who’s also a weather geek. Contact: