South Texas residents are being urged to take immediate precautions after the National Weather Service office in Corpus Christi issued an extreme heat warning for four counties in the region.
The warning, which covers Duval, La Salle, McMullen, and Webb counties, went into effect from noon to 8 p.m. on Thursday, June 18, 2026. Officials are calling the conditions dangerously hot and say the combination of intense heat and high humidity could push the heat index to as high as 120 degrees.
For communities in these areas, this is not a routine weather advisory. A heat index of 120 degrees falls well into the territory that health professionals classify as life-threatening, particularly for vulnerable populations such as the elderly, young children, outdoor workers, and people with chronic health conditions.
When temperatures reach this level, the human body struggles to cool itself effectively through sweating, which makes heat exhaustion and heat stroke a very real risk within a short period of time outdoors.
The National Weather Service has issued a clear list of precautions for residents across the affected counties. People are being advised to drink water and fluids regularly throughout the day, even if they do not feel thirsty, since dehydration can set in quickly during extreme heat without obvious warning signs.
Staying inside air-conditioned spaces during the peak hours of the afternoon is strongly recommended. Residents are also being asked to avoid direct sunlight as much as possible and to check in on elderly family members, neighbors, and anyone who may be living alone or without reliable air conditioning.
Children and Pets at Particular Risk
Among the most urgent warnings issued by the weather service is a reminder about the deadly danger of leaving young children or pets inside parked vehicles. Even on a day that might seem manageable, the interior of a car can reach lethal temperatures within just a few minutes when the engine is off and the air conditioning is not running.
On a day with a heat index approaching 120 degrees, that timeline becomes even shorter. Officials are asking all residents to make it a habit to check the back seat every time they exit a vehicle and to act immediately if they see a child or animal trapped inside a hot car.
A Region Already Dealing With Weather Extremes
South Texas has had a turbulent stretch of weather in recent weeks. Webb and Zapata counties were previously hit by severe storms, prompting Governor Greg Abbott to issue disaster declarations for both counties.
Zapata County opened an emergency shelter and urged residents to stay off the roads during flooding earlier this week. The shift from flooding to extreme heat within days illustrates the range of weather challenges this region faces during the summer months.
Residents in Duval, La Salle, McMullen, and Webb counties are encouraged to treat this warning seriously. Heat-related illness can escalate rapidly, and local emergency services are urging people to reach out to neighbors who may need help staying cool. Community members who do not have access to air conditioning are encouraged to visit local cooling centers during the warning period.