The astronomical start to summer was difficult to ignore for tens of millions of people in the United States in 2025.
The astronomical start to summer was difficult to ignore for tens of millions of people in the United States in 2025. A heat dome brought several days’ worth of scorching daytime temperatures, coupled with high humidity and warm nights, to many central and eastern states. New temperature records were set in Minnesota, Maryland, Vermont, and many places in between.
This map shows air temperatures across the eastern U.S. on June 24, 2025, at 2 p.m. Eastern Time, modeled at 2 meters (6.5 feet) above the ground. It was produced by combining satellite observations with temperatures predicted by a version of the GEOS (Goddard Earth Observing System) model, which uses mathematical equations to represent physical processes in the atmosphere. The darkest reds indicate areas where temperatures approached 40 degrees Celsius (104 degrees Fahrenheit).
The extreme temperatures were due to a large area of high pressure in the upper atmosphere, often referred to as a heat dome, that traps heat and humidity in the lower atmosphere, meteorologists explained. Intense heat afflicted the eastern U.S. starting June 21, with the most hazardous conditions creeping eastward from the country’s interior over several days.
Read more at NASA Earth Observatory
Image: NASA Earth Observatory image by Wanmei Liang, using GEOS data from the Global Modeling and Assimilation Office at NASA GSFC.
