Portland’s record-breaking heat wave: by the numbers

Two people lying in cots face away from the camera.  The person on the right has a hand resting on the shoulder of the person to the left

People make use of a cooling center at the Oregon Convention Center during Portland's unprecedented heat wave on Monday, June 28, 2021. The building's air conditioning provided relief from temperatures that rose to record levels.


The past several days have seen sweltering temperatures across Portland and much of the Pacific Northwest unlike anything seen in modern recorded history.

The city opened cooling centers to provide relief for people without air conditioning, roads buckled as asphalt cooked under three days of triple-digit temperatures, and reporters were left scrambling to find synonyms for “unprecedented” as record after record was met and then broken.

The “heat dome” that produced the wave of roasting temperatures is moving east, with Portland seeing some much-anticipated cooling Tuesday morning, but the changes to our climate are here to stay so similar heat events are almost guaranteed going forward.

But after the past several days, it’s worth looking back and seeing just how the heat wave stacked up, by the numbers.

52 degrees

The drop in temperature in Portland from Monday’s high of 116 degrees to the overnight low of 64 degrees. The rapid cooling marks the biggest overnight drop in temperature in recorded history for the city. The previous record, 48 degrees, occurred between Sept. 2 and 3, 1988.


Consecutive days Portland set new all-time high temperature records. Before this weekend, the previous record, set first in 1965 then most recently in 1981, was 107 degrees. Saturday recorded a high of 108 degrees, Sunday was 112 and Monday clocked in at 116 degrees, among the hottest places in the world for the day.

117 degrees

The recorded high temperature in Salem on Monday, marking the highest temperature ever recorded in western Oregon and just 2 degrees shy of the state’s all-time record of 119 degrees, which was set in Pendleton in 1898.


The number of people who went to the hospital for heat-related illnesses Sunday, according to the Oregon Health Authority. That’s a sharp increase from the number of people seeking care Saturday, when 56 people went to hospitals, and Friday, which saw 28 people seeing doctors for heat-related illnesses.

75 degrees

The low temperature overnight from Sunday to Monday in Portland. It marks the warmest low temperature ever recorded in the city. High temperatures at night are of particular concern during heat waves because the cooler nighttime hours are often the only time our bodies have a chance to recover.


The number of people in the western United States currently living in an area affected by drought, according to the U.S. Drought Monitor.


The amount by which global emissions of greenhouse gases must be cut by 2030 if we are to hold global temperatures to a rise of 1.5 degrees Celsius over pre-industrial levels, according to the United Nations’ Intergovernmental Panel on Climate Change.

While the heat dome that squatted over the Pacific Northwest for the last few days was not precisely caused by climate change, rising temperatures that are a result of increased concentrations of carbon dioxide in the atmosphere make these types of extreme weather more likely and, when they do happen, climate change makes them more intense. Some experts have attributed an extra 3 to 5 degrees Fahrenheit of warming during our last heat wave solely from the heat-trapping contributions of greenhouse gases.



High temperature, Saturday, June 26

Record: 102 degrees, set in 2006

Forecast: 106 degrees

Broken: Yes (108)

High temperature, Sunday, June 27

Record: 98 degrees, set in 2000

Forecast: 112 degrees

Broken: Yes (112).

High temperature, Monday, June 28

Record: 100 degrees, set in 2008

Forecast: 114 degrees

Broken: Yes (116)

High temperature in June

Record: 102 degrees, set June 26, 2006

Broken: Yes (116, Monday)

All-time high temperature

Record: 107 degrees, set Aug. 8 and 10, 1981, and July 30, 1965

Broken: Yes (115, Monday)

Longest stretch of 100 degree days in June

Record: 2 days, set in 2006

Broken: 3 days, set Saturday through Monday.

All-time longest stretch of 100 degree days

Record: 5 days, set July 13-17, 1941

Broken: Nope



June high temperature: 105 degrees

Broken: Yes (117, Monday)

All-time high temperature: 108 degrees, first set in 1927

Broken: Yes (117, Monday)


June high temperature: 100 degrees, set in 1926

Broken: Yes (108, Monday)

All-time high temperature: 106 degrees, set in 1916

Broken: Yes (108, Monday)


June high temperature: 109 degrees, set in 2015

Broken: Yes (112, Sunday)

All-time high temperature: 119 degrees

Forecast for Tuesday: 115 degrees

Broken: TBD

The Dalles

June high temperature: 108 degrees, set in 2015

Broken: Yes (118, Monday)

All-time high temperature: 111 degrees

Broken: Yes (118, Monday)


June high temperature: 102 degrees, set in 2017

Broken: Yes (108, Sunday)

All-time high temperature: 108 degrees, set in 1972

Broken: Tied


June high temperature: 102 degrees, set in 2006

Broken: Yes (105, Saturday)

All-time high temperature: 109 degrees, set in 2020

Broken: Yes (113, Sunday)
