NASA: A July of Extremes – Heatwaves Caused 1,000s of Deaths Across the Globe

At the beginning of July 2022, NOAA’s monthly climate outlook favored temperatures well above average across much of the United States. The outlook proved prescient.

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Around the globe in summer 2022, wave after wave of heat crested and broke. Heat waves, particularly in Europe and Asia, caused thousands of heat-related deaths. On July 19, the U.K. had its hottest day ever recorded as temperatures topped 104°F (40°C).

In the U.S., the heat was pervasive and persistent as atmospheric high-pressure systems established stagnant heat domes, which placed more than 150 million people under heat warnings and advisories. Nearly every region of the continental U.S. experienced above-average temperatures. Several states saw record-breaking triple-digit highs, some for days on end. With the added impact of high humidity in many regions, the extreme heat threatened life and health.

The animation above shows the daily maximum surface air temperature across most of the Western Hemisphere in July 2022. It was produced by combining satellite observations with temperatures predicted by a version of the Goddard Earth Observing System (GEOS) global model, which uses mathematical equations to represent physical processes in the atmosphere. The darkest red areas indicate temperatures of more than 104°F (40°C).

July began with the development of a ridge of high pressure across the central and eastern U.S., which contributed to the establishment of a heat dome in the south-central U.S. High atmospheric pressure acts like a lid, trapping hot air that dries and warms the land surface, which in turn further heats the air. In the animation, a zone of extreme heat persists throughout the month in the south-central U.S., at times expanding to the Southwest, Upper Midwest, and Southeast.

In mid- to late July, blistering heat baked the Great Plains with highs reaching 115°F (46°C) and heat indices exceeding 120°F (49°C). The heat index is the effective temperature felt by the human body when relative humidity is combined with air temperature. By July 20, more than 154 million people were under heat warnings or advisories according to the National Integrated Heat Health Information System.

Utah and Oklahoma both broke long-standing records for the most consecutive days on which temperatures exceeded 100°F (38°C). Utah saw 16 straight days of triple-digit highs, the most since the National Weather Service began keeping records in 1874.

The above map shows daily high temperatures on July 31, 2022. Late July saw the heat continuing in the Great Plains and Southeast, while rising in the West and Northeast. Newark, New Jersey, saw a record-breaking five straight days of triple-digit temperatures.

In the Pacific Northwest, where many homes lack air conditioning, several heat-related deaths were reported. Temperatures reached highs of 110°F (43°C) in Dallasport, Washington, and 114°F (46°C) in Medford, Oregon.

Extreme heat has killed more than 700 Americans per year on average over the past 30 years. Heat is the leading cause of weather-related death in the U.S., causing more deaths than hurricanes, tornadoes, floods, or extreme cold.

This post first appeared on NASA Earth Observatory. NASA Earth Observatory video and image by Joshua Stevens, using GEOS data from the Global Modeling and Assimilation Office at NASA GSFC. Story by Sara E. Pratt, with input from Steven Pawson and Nathan Arnold, GMAO.