With temperatures forecast to soar well into the triple digits, the National Weather Service (NWS) is urging the public to take precautions against potentially life-threatening conditions.

In response, Extreme Heat Warnings have been issued across seven states: Arizona, Iowa, Minnesota, Nebraska, South Dakota, Nevada, and Wisconsin.

Cities listed in the alerts include Tucson, Green Valley, Vail, Marana, Nogales, Douglas, Clifton, Safford, Benson, Willcox, Mammoth, and Oracle. In central Arizona, the warning also covers Phoenix, Goodyear, Avondale, Tempe, Mesa, Chandler, Gilbert, Glendale, Surprise, Scottsdale, and surrounding cities.

In the Grand Canyon area, lower elevations below 4,000 feet are also included, particularly Phantom Ranch, Supai, Grand Canyon Village, and the North Rim, with temperatures expected to reach between 104°F and 113°F.

In Nevada, the Las Vegas Valley, Lake Mead National Recreation Area, Overton, Indian Springs, and Pahrump are all under warning. Additional cities listed include Las Vegas, North Las Vegas, Henderson, Boulder City, and Laughlin.

In the adjacent parts of California, the warning extends to Death Valley National Park, the Eastern Mojave Desert, and western San Bernardino County. Specific cities include Barstow, Daggett, Needles, Fort Irwin, and the Mojave Preserve area.

Additional smaller towns listed include Papillion, Falls City, Albion, O’Neill, Fullerton, Ord, and Broken Bow. Counties such as Boyd, Holt, Garfield, Wheeler, and others across eastern, central, south-central, and north-central Nebraska are included.

In Iowa, western and central counties are affected. Cities listed include Des Moines, Sioux City, Fort Dodge, Carroll, Council Bluffs, Rockwell City, Emmetsburg, Estherville, Lake View, Denison, Atlantic, and Guthrie Center.

The warnings cite a combination of high temperatures and humidity that will push heat index values up to 110°F in some locations.

South Dakota is under the same warning in the southeast portion of the state. Cities specifically named include Sioux Falls, Yankton, Vermillion, Brookings, Madison, Mitchell, and Parker.

Counties affected include Lincoln, Turner, Minnehaha, Union, Clay, and surrounding areas. Heat index values in these locations are forecast to exceed 105°F, with very warm nighttime lows increasing health risks.

Counties listed include Renville, Blue Earth, Brown, Nicollet, Le Sueur, Kandiyohi, Meeker, McLeod, Steele, Sibley, and Waseca. In Wisconsin, affected areas include Hudson, River Falls, and counties like Pierce, St. Croix, and Polk.

Areas Under Extreme Heat Watch

In North Dakota, areas near the Minnesota border will be under an Extreme Heat Watch Sunday afternoon through evening. The alert includes cities such as Bemidji, Bagley, Mahnomen, Detroit Lakes, Red Lake, Park Rapids, and Baudette.

Counties named in the alert are Beltrami, Hubbard, Lake of the Woods, Mahnomen, Becker, and Clearwater. Forecasts indicate heat index values could reach close to 100°F, raising health concerns for outdoor exposure.

Across Iowa and northwest Illinois, a separate watch begins Saturday afternoon and runs through Sunday evening. Affected communities include Davenport, Bettendorf, Iowa City, Cedar Rapids, Burlington, Mount Pleasant, Muscatine, Fairfield, Maquoketa, Clinton, Tipton, Dubuque, and Moline.

In Iowa, the alert spans counties such as Johnson, Scott, Washington, Linn, Muscatine, Dubuque, Keokuk, Des Moines, Henry, Louisa, Jefferson, and Lee. Illinois counties include Rock Island and Mercer. Heat index readings are forecast to exceed 105°F, and warm nighttime temperatures in the upper 70s may prevent the body from cooling down adequately.

Southern parts of Illinois and eastern Missouri are also facing a prolonged heat watch that begins Saturday and continues through Tuesday evening. This alert targets the St. Louis metro area, including cities like St. Louis, St. Charles, Alton, Cahokia, Belleville, and Edwardsville.

What the Public Should Do

For areas under an Extreme Heat Warning, the NWS advises immediate action to avoid heat-related illness. People are urged to stay indoors as much as possible, preferably in air-conditioned buildings. Those who must be outside should limit activity to early morning or evening hours, and wear lightweight, loose-fitting clothing.

It is essential to stay hydrated, avoid alcohol and caffeine, and take frequent breaks in the shade or indoors. The warnings also advise checking on elderly individuals, children, and those without adequate cooling, and stress that children and pets should never be left in vehicles, even briefly, due to the rapid rise of temperatures inside cars.

The risk of heat exhaustion or heat stroke is highest during the afternoon and early evening when temperatures and humidity peak.

For areas under an Extreme Heat Watch, the guidance focuses on early preparation. The NWS encourages residents to monitor forecasts, review safety plans, and make sure they have access to cooling options and sufficient water in case a warning is issued.

People are advised to begin limiting strenuous outdoor activities and to ensure at-risk groups, including older adults and individuals without air conditioning, are prepared for potentially dangerous heat.

The watch bulletins also suggest rescheduling outdoor events, checking on neighbors, and preparing for potential power or cooling system strain if extreme conditions develop.

These precautions are particularly urgent as the U.S. continues to face growing heat-related dangers.

According to a report published in the Journal of the American Medical Association in August 2024, more people in the U.S. died from heat in 2023 than in any other year on record, with more than 2,300 deaths attributed to extreme temperatures.

This record toll occurred during what scientists confirmed as one of the hottest years ever recorded on Earth. Health officials and meteorologists warn that such conditions are no longer rare, making early preparedness and public awareness more critical than ever.