San Antonio Sizzles as Brutal Heat Wave Broils Alamo City Through Workweek

San Antonio is heading into another punishing day of summer heat, with temperatures climbing from the mid-70s early Sunday to about 104 degrees by late afternoon. The heat index could reach 103, and the region’s Heat Advisory remains in effect through 7 p.m. Wednesday, August 26.

Sunday Heat Builds Under Mostly Sunny Skies

Early Sunday readings were around 75 degrees with humidity near 71% and calm winds. Skies will stay mostly sunny, while south-southwest winds remain light at 5 mph or less for much of the day.

The National Weather Service Austin/San Antonio office says the broader advisory area could see heat-index values as high as 110. Residents should drink plenty of fluids, limit strenuous outdoor activity during the afternoon, and use air conditioning or other cool spaces when possible, according to the NWS Austin/San Antonio.

Triple-Digit Highs Continue Through Wednesday

Sunday night will remain mostly clear, with a low near 77 and a south wind of 5 to 10 mph. Monday and Tuesday will each reach about 102 degrees, while overnight lows stay in the upper 70s.

Wednesday is expected to bring another sunny 102-degree afternoon, with little meaningful relief from the heat. Rain chances remain near zero through most of the first half of the week, so a passing shower is unlikely to provide much help.

A Small Rain Chance Arrives Thursday

The forecast finally offers a slight change Thursday, when a 20% chance of showers and thunderstorms enters after 1 p.m. Thursday’s high should still reach about 102, followed by mostly clear conditions Thursday night.

Friday and Saturday remain hot but edge down slightly, with highs near 101 and 100 degrees. The forecast calls for mostly sunny or sunny skies, light southerly winds, and only a minimal chance of rain across the weekend.