More than 185 million people from South Dakota to Florida and up the East Coast to Boston are under alert for extreme heat this week. The National Weather Service warns that parts of the Southeast will experience the most intense conditions. On average, nearly 2,000 Americans die from extreme heat each year, according to CDC data from 2020.

On Monday, the highest temperatures will be concentrated in the Southeast, particularly from the Carolinas to Florida. Heat indices, which factor in humidity, are expected to range from 105 to 113 degrees. Some areas in Mississippi and Louisiana may see heat indices soar to 120 degrees.

The Midwest is also bracing for extreme heat, with temperatures feeling like 97 to 111 degrees over the weekend from Lincoln, Nebraska, to Minneapolis. The Northeast, including major cities like Philadelphia, New York City, and Boston, is forecasted to experience dangerous heat for several days. Heat indices in this region are expected to feel like the mid-90s to 113 degrees on Monday.

In addition to the heat, smoke from Canadian wildfires is creating hazy conditions in New York City, New Jersey, and Connecticut. Over the weekend, this smoke prompted air quality alerts in several areas.

Looking ahead, life-threatening heat and humidity are expected to persist across the eastern United States through Wednesday. Major cities such as St. Louis, Memphis, Charlotte, Savannah, Tampa, and Jackson, Mississippi, are likely to see actual temperatures in the upper 90s to low 100s.

A prolonged heat wave is anticipated, driven by an influx of tropical moisture, which will elevate feels-like temperatures to between 105 and 115 degrees over consecutive days. Nighttime and early morning temperatures are not expected to provide relief, remaining in the 70s or higher.

From Monday to Wednesday, large portions of the Southeast will be under an extreme heat risk, rated at a four-out-of-four level. This includes cities like Atlanta, Charlotte, Jacksonville, and Tallahassee, Florida. Notably, Tampa broke an all-time heat record on Sunday, reaching 100 degrees for the first time in 130 years of record-keeping.