Extreme heat warning covers San Antonio and much of South and Central Texas

The National Weather Service has issued an extreme heat warning for San Antonio and much of South and Central Texas on Thursday, June 18, as dangerous humidity and high temperatures combine after earlier storms and flooding.

The warning is in effect from noon to 8 p.m. Thursday and includes San Antonio, New Braunfels, San Marcos and Austin. Forecasters say heat index values in the San Antonio area could reach 113 to 115 degrees, with readings as high as 119 degrees farther south and west in places such as Eagle Pass and Laredo.

The region has already seen heavy rain this week. San Antonio recorded 2.6 inches of rain on Monday, June 15, and forecasters say that recent moisture is helping drive up humidity, making the heat feel more dangerous than the thermometer alone suggests.

Heat builds after storms

Wednesday, June 17, is expected to be hot as well, with San Antonio highs around 92 degrees and heat index values near 101 to 104 degrees. Thursday is forecast to be hotter, with actual highs around 95 to 97 degrees in the city.

The Texas Hill Country is under a heat advisory rather than an extreme heat warning. There, heat index values are expected to reach about 108 to 112 degrees.

Who is most at risk

Extreme heat can quickly become dangerous for outdoor workers, commuters and people without reliable air conditioning. Children, pets and older adults are also at higher risk.

Health and safety guidance during extreme heat typically includes drinking water, limiting outdoor activity during the hottest part of the day, taking breaks in shade or air conditioning and checking on vulnerable neighbors.

The warning comes after flooding and thunderstorms affected parts of South and Central Texas earlier in the week, creating a sharp swing from wet weather to oppressive heat.

What to watch next

Forecasters will be watching whether the warning is extended or updated beyond Thursday evening. Local governments may also issue additional guidance or open cooling centers if conditions warrant.

Any additional rain chances later in the week could alter the heat outlook, but for now the immediate concern is the combination of high temperatures and elevated humidity across the region.