The US National Weather Service has issued a warning about a severe heatwave caused by a "Heat Dome" phenomenon covering over two-thirds of the country, with temperatures 8-14 degrees Celsius above normal, posing health risks and escalating wildfire dangers.
On 12 July 2026 GMT+7, the US National Weather Service warned that the United States is facing a major "Heat Dome" event, which will cause abnormal temperature spikes across nearly two-thirds of the country. The heatwave is expected to start this weekend and may last at least one week, with some areas affected through the end of the month.
Meteorologists predict that many areas will experience temperatures 8-14 degrees Celsius above average during both day and night. The persistently high nighttime temperatures are a significant risk factor because the body cannot effectively cool down and recover, and this also increases wildfire risk in several states.
Daniel Swain, a climate scientist at the University of California, stated that this heatwave is especially severe regarding the affected area, intensity, and duration, impacting millions of people nationwide.
The Heat Dome phenomenon occurs when high atmospheric pressure covers a large area, acting like a lid that traps hot air beneath while blocking cooler winds and rain. This leads to continuous temperature buildup. Initially, the center of the heat dome will cover the northern Great Plains before expanding its influence over most of the US, potentially spreading from the West Coast to the East Coast within the next 10 days.
Weather forecasters expect states including Nevada, Utah, Colorado, Wyoming, Idaho, Montana, North Dakota, and South Dakota to see temperatures exceeding 38 degrees Celsius, with new records likely in many locations.
The US National Weather Service also indicated that by Wednesday, more than 90 local temperature records could be broken or matched, with over two-thirds of these being nighttime temperature records.
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