Around 100 million people across the United States are facing dangerous temperatures this week as a powerful heat dome expands from the western states toward the Northeast, bringing widespread heat warnings, record-breaking temperatures and an elevated risk of wildfires.
Meteorologists expect temperatures across large parts of the country to remain 20 to 30 degrees Fahrenheit above seasonal averages, with some locations likely to set new daily and all-time temperature records over the coming days.
Record Heat Across the West
Several western states have already experienced exceptional heat. Billings, Montana, reached a record 111°F (43.9°C) on Sunday, while Salt Lake City recorded an all-time high of 109°F (42.8°C), surpassing its previous record of 107°F, which had stood since being matched several times between 1960 and 2022.
Most of Utah remains under an Extreme Heat Warning, while dangerous conditions have also spread across the Great Basin, the Rocky Mountains and parts of the desert Southwest.
Heat Dome Expands Toward the East
The heat dome—an atmospheric high-pressure system that traps hot air over a region—is expected to push eastward during the week. Forecasters expect the Northern Tier to experience peak temperatures on Tuesday, followed by the Northeast on Wednesday.
Heat index values, which combine temperature and humidity, are forecast to climb into the upper 90s and exceed 100°F (37.8°C) across a broad swath of the country for several consecutive days.
Warnings Issued Across Multiple States
Extreme Heat Warnings have been issued across large areas of Utah, North Dakota and South Dakota, with additional heat advisories stretching across much of the western and central United States.
The National Weather Service described the prolonged heat as “exceptionally rare” for some locations, even during the middle of July, warning that hazardous conditions could persist into next weekend across parts of the central United States.
Wildfire Risk and Health Concerns Increase
The prolonged period of hot, dry weather is also increasing wildfire danger across the western states. In California, the Summit Fire in the Antelope Valley burned nearly 3,000 acres, prompting temporary evacuation orders for residents north of Los Angeles.
Fire crews had contained approximately 31% of the blaze by Sunday evening, while authorities continued monitoring weather conditions that could accelerate fire activity.
Health officials are urging residents to limit outdoor activities during the hottest parts of the day, remain hydrated and check on vulnerable family members and neighbours. The combination of extreme daytime temperatures and unusually warm overnight conditions significantly increases the risk of heat exhaustion and heat stroke, particularly among older adults, young children and people with chronic medical conditions.
Forecasters expect Southern California, Arizona and much of the desert Southwest to remain under dangerous heat through at least Thursday, while millions more people across the eastern United States prepare for the arrival of the expanding heat wave.
