The record-breaking heat sweeping through the Southwest is continuing, meteorologists said, and they expect it to expand eastward before it eases—potentially keeping large parts of the country in conditions that would normally arrive later in the year. The pattern has been driven by a heat dome, meteorologists said, in which high pressure acts like a lid that traps warm air over a broad region.
On Monday, Gregg Gallina of the National Weather Service’s Weather Prediction Center said the “area of record temperatures is extremely large” and described the overall reach of the warming as abnormal on a national scale. He added that the heat may last into early April, saying it was not going away quickly and “maybe not till the middle of the next week as April starts,” as forecasters watch how the system evolves.
Forecasting for the next several days points to an eastward expansion of the hottest conditions. Gallina said the dome’s movement could mean temperatures in the 90s Fahrenheit for parts of the southern and central Plains by Wednesday, with a broad swath of the continental U.S. close to or flirting with March record highs.
Meteorologists also linked the persistence of record-level warmth to the geometry of the weather pattern. Jeff Masters of Yale Climate Connections said Flagstaff, Arizona, could see 11 or 12 consecutive days with temperatures higher than the city’s previous March record, a stretch tied to how the dome holds over the region. Both Masters and Gallina described the jet stream pattern as a factor, saying it remained stalled far westward, while other weather systems approached the country from other directions—including storms that were dropping heavy rain in Hawaii.
The heat has already produced multiple record results in the Southwest and the data show how extreme it has been for March. On Friday, four places in Arizona and California reached 112 degrees, according to the Weather Service, and one of the reported impacts was the breaking of the record for the hottest March day in the continental U.S. by 4 degrees. The same Friday peak was also described as just 1 degree shy of the hottest day recorded in the Lower 48 in April, underscoring how late-season the March weather has become.
Researchers tracking global weather records compiled a broader state-by-state context, saying 14 states have set their hottest March day on record since the heat dome began. Maximiliano Herrera, who tracks global records, said the list includes California, Arizona, Nevada, Kansas, New Mexico, Nebraska, Utah, South Dakota, Missouri, Iowa, Colorado, Wyoming, Minnesota and Idaho, and he wrote that record temperatures were also being broken in Mexico during the same pattern.
As the event unfolded, the National Center for Environmental Information registered record breaks at weather stations across the country. The center’s network showed at least 479 stations breaking March records from Wednesday through Saturday, while Herrera said the true number was likely higher based on a broader data set. The center also said an additional 1,472 daily records—records that are generally easier to break—were shattered during the same period.
Meteorologists and weather historians compared the current episode with other major heat waves. Weather historian Chris Burt, author of “Extreme Weather,” said the physical area affected by this heat wave likely dwarfs two other widely discussed historic events: one in 2012 in parts of the Upper Midwest and Northeast and another in 2021 across the Pacific Northwest. Burt said those other heat waves were more intense and were often worse for people because the hottest temperatures fell in summer months, while this event has stayed concentrated as a single big episode.
Scientists who assess the role of human-caused climate change said the hotter conditions were strongly influenced by greenhouse-gas emissions. On Friday, a group of international climate scientists with World Weather Attribution determined that the record heat was “virtually impossible” without climate change and “800 times more likely” because of warming driven by burning coal, oil and natural gas. Report co-author Clair Barnes, an Imperial College of London scientist with the group, said the added effect was at least 4.7 degrees Celsius (2.6 degrees Celsius).
Looking ahead, Masters said the heat dome would move on by late next week and said the key was time. “We just have to give it time,” Masters said, as forecasters continue to track the shifting air-pressure system and its likely reach beyond the Southwest.