San Antonio is bracing for a dangerous heat wave, with temperatures expected to climb into the low 100s and humidity pushing heat index values to a sweltering 112 degrees. The National Weather Service has issued a Heat Advisory from noon to 8 p.m. on Wednesday, covering areas along the Interstate 35 corridor and east, including all of Bexar County.

The forecast predicts highs between 100 and 104 degrees on Wednesday, with humidity making the feels like temperatures soar into the triple digits. This hot and humid pattern is expected to continue through Thursday before temperatures settle into the upper 90s through early next week.

Shift to typical late-summer weather pattern

The return of triple-digit heat marks a shift back to a more typical late-summer weather pattern after weeks of frequent rain and milder temperatures. Bianca Garcia, a meteorologist with the National Weather Service’s Austin/San Antonio office, explained that this pattern is expected to bring triple-digit temperatures especially in the Texas Hill Country and areas along and east of the I-35 corridor.

While the temperatures are seasonal for late July, the humidity will make conditions feel significantly hotter, increasing the risk of heat-related illnesses. The Centers for Disease Control and Prevention’s HeatRisk forecast estimates a moderate heat risk across Bexar County on Wednesday, climbing to a major risk on Thursday. Vulnerable groups, such as those without adequate cooling or hydration, are particularly at risk.

Tropical Storm Bertha’s influence on the heat

The hot pattern is being reinforced by Tropical Storm Bertha, forecast to move toward the Upper Texas Coast later this week. South Central Texas, remaining on the storm’s western side, is expected to stay on the hotter, drier side of the system rather than receive widespread rainfall.

Garcia noted that while the storm could provide some limited relief if isolated showers develop over South Central Texas later this week, the primary expectation is for continued high temperatures. “When we are on the western side of any sort of tropical system, we do remain on the dry, rain-free, and hot side,” Garcia said.

Heat mitigation resources and safety tips

With several days of dangerous heat expected, city and weather officials are urging residents to take precautions to reduce the risk of heat-related illness. The National Weather Service recommends staying hydrated, taking frequent breaks in the shade, and limiting strenuous outdoor activity during the hottest part of the day.

The City of San Antonio is encouraging residents to spend time in air-conditioned spaces whenever possible and has compiled an online hot weather resource page with heat safety information and other community resources. Residents needing relief from the heat can use the city’s interactive “Places to Stay Cool” map to find nearby libraries, senior centers, and community centers that are open during normal business hours.

City officials also recommend drinking water throughout the day, wearing lightweight, loose-fitting, light-colored clothing, and checking on older adults, young children, people with chronic medical conditions, and neighbors without air conditioning. Learning the warning signs of heat exhaustion and heatstroke and calling 911 immediately if someone shows signs of heatstroke is crucial.

Officials also reminded residents never to leave children or pets unattended in vehicles. Pet owners should ensure animals have access to fresh water, shade, and shelter, avoid walking dogs on hot pavement, and watch for signs of heat stress. Residents concerned about an unsheltered person who may need assistance during the heat can contact the City’s Community Connections Hotline at 210-207-1799.

More information about heat safety, cooling locations, and available city resources is available at the SA.gov/HotWeather.