San Antonio woke Monday, July 13, 2026 to cloudy, muggy skies, with temperatures starting near 80°F and a daytime high headed for about 91°F. The bigger story is what comes next, as a multi-day stretch of showers and thunderstorms is set to kick off tonight, bringing locally heavy downpours and pockets of flash flooding through Thursday.
Tonight’s Threat And The Evening Commute
Forecasters expect showers and thunderstorms to start popping Monday evening, with a chance between about 7:00 p.m. and 10:00 p.m. on Monday, July 13, then a higher likelihood from roughly 10:00 p.m. to 1:00 a.m. Tuesday, July 14. Periods of rain are expected to continue overnight. Lows should hold near 76°F with sticky conditions, and the forecast discussion notes heat index readings up to about 101°F while storms develop. Many spots could see new rainfall amounts of a quarter to a half-inch to start.
According to the National Weather Service Austin/San Antonio, the best chances for heavy rain run from Monday night through Thursday, and forecasters caution that “a Flood Watch could be needed” for parts of the region if the wetter scenarios play out.
How Much Rain Could Fall
Rain totals will depend heavily on which neighborhoods get parked under the slow movers, but forecasters warn that sluggish thunderstorms could drop multiple inches of rain in a short time. Guidance cited in the updated forecast discussion points to several-day totals of 2–6 inches from Monday through Thursday for many locations, with isolated pockets near 8 inches possible where storms stall…