A Arizona desert town hit 110°F on March 19, 2026, setting a U.S. record for the hottest March day.

A desert community near Martinez Lake in southwestern Arizona recorded 110°F (43.3°C) on March 19, 2026, setting a new U.S. record for the highest March temperature, according to the National Weather Service. The extreme heat, part of a widespread winter heat wave, affected the Southwest, with Phoenix, Las Vegas, Los Angeles, San Diego, and other cities experiencing their hottest March days in decades. Many locations saw their earliest 100°F days on record, weeks ahead of historical averages. Temperatures across the region were 20 to 30 degrees above normal, prompting heat advisories and trail closures. The heat wave was expected to ease slightly by Sunday but remained unusually intense for March.