US Southwest Heat Dome Drives Record Temperatures Across Multiple States

A high‑pressure ridge over the northern Rockies created a heat dome that pushed extreme temperatures across the western United States in mid‑July 2026. Weather stations in Billings and Miles City, Montana, recorded 111 °F and 115 °F respectively, while Sheridan, Wyoming reached 109 °F, all breaking long‑standing all‑time records. In Utah, cities such as Salt Lake City (109 °F) and Deseret (111 °F) also set new highs.

The heat dome moved eastward, prompting forecasts of triple‑digit temperatures in the Midwest, New England and the Mid‑Atlantic. Health officials warned that “even for mid‑July, this heat is expected to be exceptionally rare for some locations,” and CDC data showed a tenfold rise in heat‑related emergency‑department visits in the Mountain states. The extreme heat threatens vulnerable populations, strains electricity demand, and raises risks of dehydration, heat stroke and other heat‑related illnesses.

Meteorologists note that such heat domes have become more frequent, with the number of U.S. summer heat waves roughly doubling since 1980. Continued monitoring is expected as the system advances eastward, with potential for further record‑breaking temperatures and associated health and infrastructure impacts.