An intense heat wave is poised to blanket 16 U.S. states, impacting over 80 million Americans as the nation grapples with one of its hottest summers on record. The new heat dome, centered over the southern U.S., is expected to push temperatures in several states toward 100 degrees Fahrenheit, challenging or breaking long-standing records.
The National Weather Service (NWS) has issued heat advisories across 12 states, with heat index values predicted to reach between 105°F and 111°F. This 'feels like' temperature, exacerbated by high humidity, is anticipated to persist through at least Tuesday.
This latest surge of heat follows a summer that has already seen numerous record-breaking temperatures. According to AccuWeather data, 2026 has been the hottest summer on record for Arizona, Colorado, New Mexico, and Utah. Several other states, including California, Nevada, Idaho, Texas, Louisiana, Florida, the Carolinas, Delaware, and Maine, have experienced summers that rank among their top five hottest.
The current heat dome is described as acting like a "steam cooker," trapping heat and humidity and preventing cooler air from descending. The most extreme conditions are expected in Texas, Oklahoma, Louisiana, and Arkansas, with predictions of reaching 100°F. San Antonio, Texas, may break a 15-year-old record if temperatures hit the forecasted 98°F, just shy of the city's all-time high for the date. In Fort Smith, Arkansas, a high of 102°F is predicted, which would surpass a record set in 2000.
Health officials are urging residents to take precautions against heat-related illnesses. Recommendations include drinking plenty of fluids, staying in air-conditioned spaces, avoiding direct sun exposure, and checking on vulnerable relatives and neighbors.
This late-season heat wave follows a global trend, with August 2026 having been declared the hottest month ever recorded on Earth. AccuWeather noted that while record heat remains rare, it is occurring with increasing frequency. Experts suggest that rising average global temperatures are lowering the baseline, making it easier for extreme heat events to set new records.
The analysis from AccuWeather utilized data from the NOAA Centers for Environmental Information (NCEI), which has maintained climate records for 132 years. Arizona, in particular, experienced its hottest summer ever, with temperatures averaging over five degrees Fahrenheit higher than a typical summer.
The emergence of El Niño this summer could also influence weather patterns globally through the fall and winter, according to AccuWeather Expert Meteorologist Tyler Roys.