Tacna hits 111 degrees, sets Arizona March heat record

Tacna’s 111 degrees on March 20 did more than break a number. It pushed western Yuma County into summer-like heat weeks early, forcing farm crews, outdoor workers and families to rethink work hours, cooling demand and heat safety before April even began.

The National Weather Service in Phoenix said Tacna’s reading set the new Arizona record high for March 2026 and marked the warmest March temperature recorded at an established National Weather Service location in Arizona since record keeping began in 1895. In Yuma, the month looked more like peak summer than spring. The city’s average March temperature reached 93.4 degrees, 13.2 degrees above normal, while the National Weather Service says Yuma’s average first 100-degree day is May 2 and the average first 110-degree day is June 11 under the 1991-2020 climate normal.

The heat did not stop at the county line. Phoenix averaged 78.8 degrees for March, 12.5 degrees above normal and 6.5 degrees hotter than its previous March record from 2004. Phoenix also broke daily record highs on 15 days, logged nine days at 100 degrees or above and reached 100 on March 18, its earliest triple-digit day of the year. On March 20, four places in Arizona and California hit 112 degrees, a reading that broke the record for the hottest March temperature ever recorded in the United States and placed Martinez Lake and Fort Yuma in the same record-setting stretch.

That matters in Yuma County, where more than 65,000 farmworkers keep the region’s agricultural economy moving, including about 16,000 migrant workers and roughly 50,000 seasonal workers. County emergency guidance says heat waves have caused more deaths, on average, over the last 10 years than any other weather hazard, including tornadoes, hurricanes and flooding. It urges residents and outdoor workers to drink water, watch for heat illness and avoid overexertion between 11 a.m. and 6 p.m.

Climate scientists said the long March heat was intensified by human-caused climate change, and the record numbers fit a larger pattern of early-season warming across the West. For Tacna and the rest of western Yuma County, the 111-degree reading was not just a line in the record book. It was a warning that the hottest part of the year may be arriving before spring is over.