The National Weather Service reported on August 25, 2026, that more than 80 million people in the United States are currently under extreme heat warnings or heat advisories. Forecasters identified a heat dome bringing temperatures described as a "steamy air-mass" that is expected to continue through the week. High temperatures are forecasted to persist across the South-Central U.S. and expand into the Southwest by mid-week.
This weather pattern follows a trend of increasing heat intensity reported by the National Climate Assessment. The number of heat waves in the U.S. has doubled since the 1980s, and scientists from the Lawrence Berkeley National Laboratory state that climate change has increased the temperature of typical heat waves by 3 to 5 degrees Fahrenheit. Additionally, the Trump administration recently implemented budget cuts to the National Oceanic and Atmospheric Administration (NOAA) and the National Weather Service.
Daytime temperatures are expected to exceed 100 degrees Fahrenheit in the Southern Plains and Lower Mississippi Valley, while the Southwest may see highs reaching 110 degrees or more. The National Weather Service noted that overnight temperatures will remain high, providing little relief for residents. Michael Wehner, a senior scientist at Lawrence Berkeley National Laboratory, stated that human-caused global warming makes the most intense heat waves possible, citing recent European heat waves as an example.
For residents in the affected areas, the heat index—which measures how temperature feels when combined with humidity—is expected to range between 105 and 115 degrees this week. This level of humid heat prevents sweat from evaporating, hindering the body's natural cooling process. Vulnerable groups, including those without reliable air conditioning or those who work outdoors, face a heightened risk of death, as heat is currently more lethal than hurricanes, wildfires, and floods combined. Beyond immediate health risks, a study reported by NPR indicates that rising nighttime temperatures are causing individuals to lose up to 56 hours of sleep annually.
The broader impact involves a permanent shift in U.S. weather patterns, with heat waves now occurring twice as frequently as they did in the 1980s. This frequency strains local infrastructure, including air conditioning systems and energy grids. The recent cuts to NOAA and National Weather Service funding may also affect future forecast improvements and hurricane monitoring. While dangerous conditions are expected to persist through the end of this week, scientists continue to monitor the long-term influence of fossil fuel emissions on the frequency of these record-breaking events.