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A punishing heat dome expanded across the central United States this weekend, pushing temperatures above 100 degrees from Texas to North Dakota and placing roughly 80 million Americans under heat advisories, even as forecasters warned the dangerous conditions would persist well into next week.

Heat dome grows across the central US

Forecasters said Saturday that a ridge of high pressure trapping hot air over the Plains and Midwest was expected to expand further, stretching from Dallas to North Dakota and pushing daytime highs into triple digits across a wide swath of the country. Overnight lows were not expected to drop enough to give residents meaningful relief, a pattern forecasters said would allow heat stress to build cumulatively over consecutive days. High humidity across parts of the region is compounding the danger, pushing heat index values — how the temperature actually feels on the body — well above the measured air temperature in states including Iowa and Arizona.

The current heat dome follows two earlier waves of extreme heat that struck North America earlier this summer. A heat dome parked over the eastern United States and eastern Canada from late June through early July, with Atlantic City, New Jersey, reaching 106 degrees on July 4. A second dome then formed over the western and central U.S. in early July, sending Phoenix to a high of 113 degrees over multiple days and pushing Salt Lake City to a new all-time record of 109 degrees on July 12. That same week, a ridge over the northern Rockies drove record highs in Montana, Utah and Wyoming, with weather stations in Billings and Miles City, Montana, and Sheridan, Wyoming, all recording their hottest temperatures since record-keeping began.

Nationally, more than 1,400 daily heat records had fallen in July through the 19th, on top of roughly 1,035 broken in June, according to meteorological trackers monitoring the season. No new all-time state temperature records have fallen so far this summer, but forecasters say the pattern is keeping pressure on some of the most extreme heat marks in U.S. history.

Danger extends beyond desert states

While Arizona and the Southwest remain accustomed to extreme summer heat, this month's dome has pushed dangerously high temperatures into states less equipped to handle them. Kansas was forecast to approach 113 degrees, with Oklahoma and Texas expected to climb near 112, according to European weather modeling cited by forecasters. South Dakota was expected to near 109 degrees, while temperatures above 105 were forecast across parts of Arkansas, Colorado, Idaho, Louisiana, Minnesota, Mississippi, Missouri, Montana, Nebraska, New Mexico, North Dakota, Tennessee, Utah and Wyoming. Iowa and Wisconsin were expected to surpass 100 degrees as well, with humidity pushing perceived temperatures notably higher across the Plains and Gulf Coast.

Public health officials have repeatedly warned that the combination of high heat, elevated humidity and limited overnight cooling creates especially dangerous conditions for people working or exercising outdoors, as well as for those without reliable access to air conditioning.

A summer of extremes in the UK as well

Across the Atlantic, the United Kingdom is enduring its own historic summer. The country entered its third heatwave of 2026 in early July, following record-breaking hot spells in May and June that already made this year's meteorological summer one of the most extreme on record. A provisional reading of 37.3 degrees Celsius, or about 99 degrees Fahrenheit, was recorded at Santon Downham in Suffolk on June 26 — the hottest June day ever documented in the UK, breaking a record that had stood since 1976.

By mid-July, the UK had recorded more days above 30 degrees Celsius than the whole of 1976 combined, and became the first year on record in which temperatures reached 35 degrees Celsius in May, June and July alike. Met Office science manager Dr. Amy Doherty said the milestones reflect an unusually persistent pattern this year. "This year has already seen a number of remarkable temperature milestones," Doherty said, pointing to a record eight days above 34 degrees Celsius, surpassing the previous mark shared by 1976 and 2020.

The extended heat has strained UK infrastructure and water supplies. Severn Trent Water, which serves the West Midlands, reported its highest single-day demand on record on July 11, while Thames Water announced a temporary hosepipe ban beginning July 23 — a measure it had avoided since 1995 in the case of Severn Trent. Health officials have also linked the extreme heat to a significant rise in mortality, with one estimate suggesting more than 2,700 people may have died as a result of the exceptional May and June heatwaves in England and Wales combined.

Climate scientists point to a broader pattern

Researchers studying this year's back-to-back heat events in North America and Europe have said the frequency and intensity of the extremes are consistent with the influence of human-caused climate change, which studies have repeatedly linked to the increasing likelihood of extreme heat events becoming more common, more intense and longer-lasting. A study examining earlier stretches of this year's heat found the events would have been extremely unlikely without the influence of fossil fuel-driven warming.

Forecasters say the current U.S. heat dome is expected to persist through at least the coming week, with little relief anticipated for the central Plains states bearing the brunt of the latest wave. In the UK, meteorologists have noted that this summer's heat has already reshaped seasonal records across England, Wales and the wider UK, with officials continuing to monitor both public health impacts and strain on water and power infrastructure as the extended warm pattern continues.

For residents on both sides of the Atlantic, officials are urging continued caution: staying hydrated, limiting outdoor activity during peak afternoon hours, and checking on vulnerable neighbors as the extended heat wave shows few signs of easing in the days ahead.

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