Overview
- Near Martinez Lake, Arizona hit 110°F on March 19, confirmed by the National Weather Service as the hottest temperature ever recorded in the U.S. during March.
- Phoenix logged its earliest 100°F day at 102°F on March 18 and reached 105°F on March 19, with an extreme heat warning in effect through Sunday evening.
- The National Weather Service reports more than 50 March records and over 150 daily records broken across Arizona, California and Nevada since March 17.
- Forecasts show the high‑pressure ridge weakening briefly late weekend before rebuilding, keeping the Phoenix area around 100°F through much of next week.
- Health officials urge hydration and limited midday activity as cities open cooling options such as splash pads, and Martinez Lake businesses report an early surge in visitors.