The most severe heat wave in the history of the Pacific Northwest has climaxed, obliterating scores of long-standing records in both the U.S. and Canada. The National Weather Service had predicted the heat wave would be “historic, dangerous, prolonged and unprecedented,” and it has lived up to its billing.

Perhaps the most astonishing heat occurred Tuesday in British Columbia where the high temperature in the village of Lytton soared to 121 degrees, setting Canada’s national heat record for a third straight day. For perspective, this temperature is more extreme than the all-time high in Las Vegas, 117, and higher than most places in the Lower 48 states outside the Desert Southwest.

“Words cannot describe this historic event,” tweeted Environment Canada’s British Columbia branch.

According to world weather records expert Maximiliano Herrera, the 121-degree reading also set a new world record for the most extreme high temperature ever observed north of 45 degrees latitude.

Lytton broke Canada’s previous national heat record of 113 degrees on three consecutive days, rising to 116 Sunday, 118 Monday and finally 121 Tuesday, which tied Death Valley for the day’s highest temperature in North America.

In the Lower 48 states, while the heat eased on Tuesday in Seattle and Portland, record-setting temperatures roasted the interior Pacific Northwest. Spokane, for example, set a new all-time high of 109 degrees.

A preliminary new all-time state record high temperature was set in Oregon, where Hermiston, about 185 miles east of Portland, surged to 118 degrees. This occurred just one day after Dallesport, Wash., also hit 118, preliminarily tying a Washington state record. Dallesport is located about midway between Hermiston and Portland along the Washington-Oregon border.

Tuesday’s exceptional inland heat followed a sweltering Monday when locations closer to the coast saw temperatures balloon 30 to 40 degrees above normal.

Portland and Seattle broke all-time records by enormous margins. Portland reached 116 degrees, the highest temperature in more than 80 years of record-keeping. It was the third day in a row the city set a new all-time high. Before this weekend, the all-time high was 107, but on Saturday it hit 108 and on Sunday 112.

Seattle soared to a sizzling 108 degrees Monday evening, surpassing the all-time record of 104 degrees set the day before (which topped the previous mark of 103 from 2009). The high of 108 was 34 degrees above the normal high of 74 and higher than the all-time heat record in Washington, D.C., among many other cities much farther to its south.

Medford, Ore., tied its all-time record Monday of 115 degrees.

Some places on Monday shattered all-time records, which are exceptionally rare and difficult to break, by 5 or even 10-plus degrees. For example, Quillayute, Wash., which hit 110, obliterated its previous all-time high by 11 degrees matching the largest margin for breaking such a record ever observed globally.

The strength of the heat dome, or sprawling zone of high pressure centered near the U.S.-Canada border, responsible for these temperatures has been off the charts and blowing away records. Its intensity has been so statistically rare that it might be expected only once every several thousand years on average. But human-caused climate change has made exceptional events such as this many times more probable.

“The past is no longer a reliable guide for the future. These events are becoming more frequent and intense, a trend projected to continue,” tweeted the Oregon Climate Office.

Meteorologists described the situation as “insane,” “bonkers” and “incredible.” The Weather Service in Seattle wrote that attempting to forecast heat so extreme was “disconcerting,” because no analogous situation has occurred in the past.

A heat wave is pushing temperatures to record highs in the northwestern United States and western Canada. (Christopher Vazquez/The Washington Post)

Because of the heat wave’s longevity, new record-long streaks for surpassing different temperature thresholds are also occurring. For example, Seattle experienced triple-digit heat on three straight days for the first time on record.

Officials have expressed the fear that the intensity and duration of the heat wave will lead to dramatic increases in heat-related illness and fatalities in a region where many lack air-conditioning. In British Columbia, there appeared to be a mounting death toll related to the heat.

While the intensity of the heat wave will slowly wane in the coming days, dangerously hot temperatures are forecast to continue in the interior Pacific Northwest and western Canada into the weekend. And above normal temperatures may persist even beyond that.

Here is a running list of some of the most significant records established during this unprecedented event:

All-time record highs

All-time highs are the most rare and refer to the highest temperature on record for any month at a given location.

Tuesday

  • Spokane reached 109 degrees, topping 108 in 1961.
  • Hermiston, Ore., reached 118 degrees, preliminarily a new state record for Oregon.
  • Omak, Wash., reached 117 degrees, topping 112 Monday. (Before this stretch, the max was 110 in 2015.)
  • Walla Walla, Wash., reached 116 degrees, topping 114 in 1975 and 1961.
  • Ephrata, Wash., reached 116 degrees, topping 115 in 1961.
  • Moses Lake, Wash., reached 114 degrees, topping 112 Monday and in 1961.
  • Wenatchee, Wash., reached 114 degrees, topping 109 in 2015.
  • Yakima, Wash., reached 113 degrees, topping 109 on Monday, Sunday and in 2006.
  • Pullman, Wash., reached 106 degrees, topping 105 in 2018.
  • Stampede Pass, Wash., reached 99 degrees, topping 95 Monday and a tie of 93 on Sunday. (Before this stretch, the max of 93 was from 2004.)
  • Pendleton, Ore., reached 117 degrees, topping 113 degrees on Monday and in 1961.
  • Redmond, Ore., reached 112 degrees, topping 110 on Monday and 108 Sunday. (Before this stretch, the max was 106 in 2008.)
  • Coeur D’Alene, Idaho, reached 109 degrees, topping 104 Monday. (Before this stretch, the max was 102 in 2008)

Monday

  • Portland reached 116 degrees, topping 112 from Sunday and 108 from Saturday. (Before this stretch, the max was 107 from 1981.)
  • Seattle reached 108 degrees, topping 104 from Sunday. (Before this stretch, the max was 103 from 2009.)
  • Dallesport, Wash., reached 118 degrees, topping Sunday’s 114.This temperature preliminarily ties the Washington state record. (Before this stretch, the max was 111 in 1998 and 1992.)
  • Salem, Ore., reached at least 117 degrees, topping 113 from Sunday. (Before this stretch, the max was 108 from 1927, 1941, and 1981.)
  • Vancouver, Wash., reached 115 degrees, topping 112 Sunday and 108 on Saturday. (Saturday’s 108 tied a previous mark from 2009.)
  • Medford, Ore., reached 115 degrees, tying the mark from 1946.
  • Troutdale, Ore., reached 115 degrees, topping 112 Sunday and 109 on Saturday. (Before this stretch, the max was 108 in 1977.)
  • McMinnville, Ore., reached 114 degrees, topping 111 Sunday. (Before this stretch, the max was 110 in 1926 and 1925.)
  • Hillsboro, Ore., reached 114 degrees, topping 109 Sunday. (Before this stretch, the max was 108 in 2006.)
  • Quillayute, Wash., reached 110, topping 99 from 1981. This is an unofficial world record for the largest difference between an old all-time high and a new one.
  • Olympia, Wash., reached 110 degrees, topping 105 from Sunday, 2009 and 1981.
  • Fort Lewis, Wash., reached 110 degrees, topping 104 Sunday. (Before this stretch, the max was 103 in 2009.)
  • Renton, Wash., reached 109 degrees, topping 105 in 2019.
  • Shelton, Wash., reached 109 degrees, topping 107 Sunday. (Before this stretch, the max was 104 from 2009.)
  • Everett, Wash., reached 100 degrees, tying the mark set in 2020.
  • Bellingham, Wash., reached 99 degrees, topping 96 in 2009.

Sunday

  • Roseburg, Ore., reached 113 degrees, topping 109 in 2020 and 1946.
  • Eugene, Ore., reached 111 degrees, topping 108 from 1981.
  • Hoquiam, Wash., reached 103 degrees, topping 95 from 2016.
  • Astoria, Ore., reached 101, tying the mark from 1942.

Saturday

  • Several records that were set Saturday were broken again Sunday and/or Monday and are listed above.

Record warm lows

Record warm lows refer to the warmest nighttime or morning minimum temperatures on record. The ones we present here are all-time (any month) cases.

Tuesday

  • Spokane, Wash., had a low temperature Tuesday morning of 77 degrees. This preliminarily ties the all-time warmest low in 1928.

Monday

  • Bellingham, Wash., saw a low temperature Monday morning of 66 degrees, topping 65 in 2015 and 2014.

Sunday

  • Seattle’s low temperature Sunday morning of 73 degrees was the warmest on record for any date, topping 72 from 2009.
  • Hoquiam, Wash., had a low of 65 degrees Sunday morning, topping 64 from 1992.

June record highs

These are the warmest temperatures observed during the month of June at the given locations. They are rare, but monthly records are easier to break than all-time records.

Tuesday

  • Lewiston, Idaho, reached 115 degrees, topping 112 on Monday. (Before this stretch, the max was 111 from 2015).
  • Fairchild AFB, Wash., reached 109 degrees, topping 105 on Monday and 102 on Sunday. (Before this stretch, the max was 96 in 1970 and 1955.)
  • La Grande, Ore., reached 107 degrees, topping 105 Monday and 102 Sunday. (Before this stretch, the max was 99 from 2003.)
  • Baker City, Ore., reached 103 degrees, topping 102 in 1961.
  • Meacham, Ore., reached 103, topping 101 in 2015.
  • Burns, Ore., reached 103, topping 102 in 2015.

Monday

  • Klamath Falls, Ore., reached 103 degrees, topping 101 on Sunday. (Before this stretch, the max was 100 from 1992.)
  • Alturas, Calif., reached 105 degrees, topping 102 in 1961.

Sunday

  • Pasco, Wash., reached 115 degrees, topping 111 in 2015. This also broke the Washington state record for June, but has since preliminarily been topped.

Saturday

  • Several records from Saturday were re-broken Sunday and/or Monday and are listed with that group.

Record streaks

  • Seattle hit at least 100 degrees on three straight days for the first time on record Saturday (102), Sunday (104) and Monday (108).
  • Portland hit at least 108 degrees on three straight days for the first time on record Saturday (108), Sunday (112) and Monday (116).

Notable Canadian heat records

  • Lytton, British Columbia, reached 121 degrees Tuesday, the highest temperature recorded in Canada in any month (surpassing the record of 118 set on Monday and 116 on Sunday).
  • Kamloops, British Columbia, reached 115 degrees Tuesday, topping 113 Monday and 109 Sunday.(Before this stretch, the max was 106 in 2018.)
  • Victoria International Airport, British Columbia, reached 99 degrees Sunday, topping the all-time record of 97 in 2007 and 1941.
  • Calgary, Alberta, reached 97 degrees Tuesday, topping a June record of 91 on June 14. (Before this year, the max was 90 in 2017.)
  • Banff, Alberta, reached 99 degrees Tuesday, topping the all-time record of 97 degrees Monday. (Before this stretch, the max was 95 in 2005.)
  • Prince George, British Columbia, reached 100 Monday, topping the all-time high of 97 in 1983.
  • Tofino Airport, British Columbia, reached 95 degrees Monday, topping the all-time high of 91 in 1981.
  • Watson Lake, Yukon Territory, reached 91.4 degrees Monday, tying the June mark from 2004.