A Hot Start to Spring in the Southwest In March 2026, the arrival of spring in the Northern Hemisphere brought extreme heat to the southwestern United States, with temperatures surpassing 100 degrees Fahrenheit in several states. Some locations recorded their highest March temperatures on record, marking a stark contrast to the typical spring weather. The heatwave was particularly intense on March 20, when a visualization based on GEOS-FP data highlighted the widespread and severe conditions. The model, which combines meteorological observations with physical processes in the atmosphere, showed temperatures reaching or exceeding 104 degrees Fahrenheit in the darkest red areas. Weather stations confirmed the extreme conditions, with Yuma, Arizona, hitting a record high of 109°F—28 degrees above the average for that date. Four other locations, including areas near Yuma and Martinez Lake in Arizona, as well as Ogilby and Winterhaven in California, tied for the highest U.S. temperatures that day, reaching 112°F (44°C). The heat extended beyond the U.S., with Hermosillo, Mexico, setting a new March record at 108°F (42°C). The prolonged high-pressure system responsible for the heat remained over the region for more than a week, creating dry conditions and clear skies across a vast area of the U.S. and Mexico. This system, comparable in strength to summer conditions, kept temperatures elevated and contributed to the record-breaking warmth. The National Weather Service noted the unusual persistence of the high-pressure system, which typically dissipates earlier in the spring. The extreme heat was expected to spread eastward into the U.S. Midwest and Southeast by the following week.#national_weather_service #southwest_united_states #geos_fp #yuma_arizona #martinez_lake_arizona
