Weather authorities say the first major heat wave of 2025 could be one for the record books, with much of the eastern U.S., including Mississippi, under extreme heat warnings.
The National Weather Service in Jackson said Monday that the heat index in the Magnolia State could soar as high as 110 degrees, urging residents to be prepared for the sweltering temperatures.
“Remember to stay hydrated, and take extra precautions if you will be spending a prolonged amount of time outdoors,” NWS Jackson said in a social media post.
Dangerous heat stress conditions will persist into Monday as heat index values will be in the 105 to 110 F range across much of the area. Remember to stay hydrated, and take extra precautions if you will be spending a prolonged amount of time outdoors. pic.twitter.com/Q0IIKY4J2h
— NWS Jackson MS (@NWSJacksonMS) June 23, 2025
Heat warnings cover around 190 million Americans, with record highs expected to be challenged in 28 states. Extreme heat warnings, the National Weather Service’s highest level of heat alert, are covering much of the northeastern U.S.

The high-pressure system contributing to the wave, also known as a “heat dome,” sprawls more than 1,000 miles in diameter. The “dome” effectively traps high-pressure air in one place and can linger for weeks. The current system is expected to last through the end of the week.
While real temperatures won’t reach beyond the 90s in the Magnolia State, oppressive humidity could push heat indices to historic peaks.
Click here to view tips on preparing for and weathering extreme heat.