Several southwestern United States experienced temperatures surpassing 100 degrees Fahrenheit during March 2026, with some locations recording the highest March temperatures in their historical records, according to NASA's Earth Observatory. The extreme early-season heat represents a significant meteorological event, as triple-digit temperatures are historically uncommon in the region during the spring month of March. NASA's Earth Observatory documented the heat event, noting its record-breaking nature across multiple states in the region. The agency, which monitors global land and ocean temperatures using satellite and ground-based instruments, flagged the event as notable given how early in the calendar year such extreme heat was observed. The full scope of affected states, the precise temperature readings at specific locations, and the atmospheric drivers behind the heat event were reported by NASA Earth Observatory. Readers seeking additional data, imagery, and scientific context are directed to the primary source. SOURCE: NASA Earth Observatory, https://science.nasa.gov/earth/earth-observatory/a-hot-start-to-spring-in-the-southwest/ — NOTE: This article is based solely on information provided in the NASA Earth Observatory report. Independent verification of specific station-level records and contributing climate factors has not been conducted for this summary. The NASA Earth Observatory publishes reviewed scientific content, though the specific methodology and instrumentation underlying this report have not been independently assessed by HELIX.