A baseball fan watches players warm up as temperatures hit 105F in Phoenix, Arizona, on 20 March. Photograph: Ross D Franklin/APView image in fullscreenA baseball fan watches players warm up as temperatures hit 105F in Phoenix, Arizona, on 20 March. Photograph: Ross D Franklin/APRecord-breaking heat dome expected to bring dangerous temperatures to US south-westAs wildfires rage and intense heat builds across the region, daytime highs of 110-11F (43-46C) are forecast
Surging temperatures are expected to broil more than 45 million people as a heat dome settles in across the south-western US through the end of August and into early September, according to the National Weather Service (NWS).
As wildfires rage in some parts and intense heat builds across the region, daytime highs of 110-115F (43-46C) are forecast, with limited cooling relief in the evenings and overnight. Experts predict that some record highs could be tied or broken this month and the weather agency warned of the scorching late summer heat as a potential health hazard.
“A strong upper-level ridge will remain anchored across the south-west into south-central US into late week,” the NWS shared in its short-range forecast discussion.
The agency continued: “This will maintain an abnormal hazardous heat across the region, with daytime highs of 100-110 F across the Southern Plains, while portions of the southwest will reach up to 115F. With overnight temperatures providing limited relief, heat-related illness may increase, especially for those without proper hydration and adequate cooling.”
The NWS categorizes these temperatures as Extreme HeatRisk, a level dangerous to people without proper hydration and the capacity to cool down. A so-called heat dome can occur when strong, high pressure traps hot air over a region, preventing cool air from moving in and causing temperatures to rise on the ground – and stay high.
In addition to surging temperatures in the coming days, especially in a stretch from Texas to California, the NWS is forecasting that the south-west and portions of the US Rocky Mountains and the plains will see “monsoonal moisture”, resulting in heavy scattered showers and thunderstorms.
Continued humidity and moisture in the air contribute to extreme heat risks, which can be taxing on the body.
Individuals in these regions are advised to limit outdoor activities, maintain proper hydration and cooling and wear loose and lightweight clothing, according to the NWS.
It also recommends that people check on those who are more susceptible to heat-related illness, including older adults and children. Age and certain conditions make the body less able to regulate extreme temperatures.
The NWS advises that individuals not be left alone in closed cars. A reported 34 children died in hot cars in the US in 2025, according to the organization No Heat Stroke, with cases occurring right through December in parts of the south.
Some cities that will be affected by the heat dome, including Los Angeles, announced that they will be providing access to cooling centers to provide residents with relief.
With multiple heat domes hitting regions of the US and parts of Europe, researchers warn of the correlation between the soaring temperatures and the climate crisis.
“Climate change is increasing the frequency and severity of summer extreme weather events in the mid-latitudes of the Northern Hemisphere, from record-shattering heatwaves to heavy precipitation and flooding, to prolonged droughts and more extensive wildfires, as well as compounding effects due to interactions between extreme events,” according to the US scientific journal the Proceedings of the National Academy of Sciences.
