Extreme Heat Risk Map Shows 30 States Bracing for Triple-Digit Indexes

A federal heat risk map is warning that large parts of the United States could soon face dangerous, potentially life-threatening conditions, with forecasters projecting triple-digit heat index values across dozens of states in the coming days.

Extreme heat remains the deadliest form of weather in the United States on average, and federal agencies stress that prolonged exposure to high heat index values can quickly become dangerous. The combination of heat and humidity not only increases the chance of heat exhaustion and heat stroke but can also worsen preexisting health conditions, particularly for older adults, children and outdoor workers.

The map, shared by the National Weather Service's (NWS) Climate Prediction Center (CPC) in a recent social media post, highlights states with the greatest chance of experiencing extreme heat between June 30 and July 6. The accompanying key message graphic signals that more than half of the U.S. could experience heat index values topping 100 degrees Fahrenheit in the coming days, raising concerns about public health impacts and infrastructure strain.

“Strong mid-level high pressure centered over the Southeast is forecast to shift westward and expand north and northwest, increasing chances of extreme heat for much of the Central U.S., Gulf States, and Eastern U.S.,” the message said.

Since the incoming heat is still at least a week away, local NWS offices have yet to issue warnings or watches. However, several heat-related alerts remain in place across the Southwest on Tuesday.

Heat Index: What It Means

The heat index, often referred to as the "feels-like" temperature, combines air temperature and humidity to estimate how hot it actually feels to the human body. High humidity prevents sweat from evaporating efficiently, making it harder for the body to cool itself and increasing the risk of heat-related illness.

Extreme Heat Risk Map for U.S.

States at the highest risk of extreme heat during the June 30 to July 6 period are in the Mid-Atlantic region, according to the CPC map.

“High Risk (>60% chance) of extreme heat: Indicated for parts of the Mid-Atlantic including Washington D.C. (6/30-7/2). Temperatures may reach as high as 95 deg F, with heat indices possibly reaching at least 105 deg F,” the outlook said.

A moderate risk, in which there’s a 40-60 percent chance of extreme heat, will be felt in parts of Texas, Oklahoma, Kansas and along the East Coast, stretching from South Carolina to southeastern Pennsylvania and southern New Jersey, including major cities such as Charlotte and Philadelphia.

“The Texas Panhandle and parts of western Oklahoma may reach 100 deg F with heat index values near 105 deg F (6/30-7/3),” the outlook said.

Meanwhile, a slight risk, or 20-40 percent chance of extreme heat, is “indicated for much of the eastern U.S. and parts of the Great Plains (6/30-7/6).”

“Temperatures may reach at least 90 deg F, with heat index values possibly reaching 100 deg F or higher for lower elevations,” the outlook said. “Record high nighttime temperatures in the high 70s to low 80s deg F are possible.”

States at risk of extreme heat are Colorado, South Dakota, Nebraska, Kansas, Wyoming, New Mexico, Texas, Oklahoma, Iowa, Missouri, Arkansas, Louisiana, Mississippi, Alabama, Georgia, Florida, Tennessee, Kentucky, Illinois, Indiana, Ohio, West Virginia, Virginia, Virginia, North Carolina, South Carolina, Maryland, Delaware, Pennsylvania, New Jersey and New York.

Heat Exhaustion vs. Heat Stroke: Symptoms to Watch for

Heat exhaustion is typically the body's early warning sign that it is struggling to cool itself during prolonged heat exposure. Symptoms include heavy sweating, dizziness, headache, nausea, weakness and a fast but weak pulse, often accompanied by cool, pale or clammy skin. While it can usually be treated by moving to a cooler place and rehydrating, officials warn it should not be ignored, as it can quickly worsen if left untreated.

Heat stroke is a life-threatening emergency in which the body loses its ability to regulate temperature. Body temperature can rise above 103 degrees Fahrenheit, and symptoms often include confusion, slurred speech, severe headache, a rapid strong pulse and loss of consciousness, with skin turning hot and either dry or damp. Unlike heat exhaustion, mental changes are a key warning sign, indicating the brain is being affected. Health officials stress that heat stroke requires immediate medical attention, as delays can lead to organ damage or death.

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This story was originally published June 23, 2026 at 1:32 PM.