San Antonio, Texas – Dangerous summer heat is making an aggressive return to South Central Texas on Sunday, July 20, with heat index values surging past 103°F by early afternoon. The National Weather Service warns that prolonged exposure outdoors—especially along high-traffic routes like I-35 and Loop 1604—could lead to heat-related illness without proper precautions.
According to the National Weather Service in Austin/San Antonio, highs near 98°F are expected Sunday, with southerly winds at 5–15 mph offering little relief. The hottest stretch of the day will hit between 1 and 5 p.m., when heat index values exceed triple digits. Drink water frequently, avoid strenuous work outside, and check on elderly neighbors or pets.
Sunday’s high temperatures will linger into Monday and Tuesday, when conditions remain mostly sunny and hot with daytime peaks near 99°F and 98°F, respectively. Evening lows won’t offer much relief either, hovering around 77°F each night. Gusts as high as 25 mph could make the dry heat feel more oppressive.
Looking ahead, the dry, sweltering pattern continues through Friday, July 25, with little chance of rain or cloud cover. This week marks one of the longest uninterrupted hot spells of July, increasing strain on air conditioning and utilities across Bexar County.
Stay weather-aware. Cooling shelters may be available for vulnerable groups, and ERCOT may issue grid updates if demand surges.
5-Day Forecast: San Antonio, TX (Sunday, July 20 – Friday, July 25)
- Sunday: Partly sunny, high near 98°F. Heat index up to 103°F. Winds SSE 5–15 mph.
- Monday: Mostly sunny, high near 99°F. Gusts up to 20 mph.
- Tuesday: Mostly sunny, high near 98°F. Continued hot with gusts up to 20 mph.
- Wednesday: Clear and hot. Low around 76°F, high near 99°F.
- Thursday: Mostly sunny, high near 98°F.
- Friday: Mostly sunny, continued hot, high near 98°F.
