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Heavy rainfall expected Wednesday night into Thursday

Flooding is possible, with lingering rain chances into the weekend

Rain chances next 7 days (Copyright KSAT-12 2026 - All Rights Reserved)

FORECAST HIGHLIGHTS

  • HOT & HUMID TODAY: Temps mid-90s, heat index near 100
  • TUESDAY: Storms Tuesday night along Rio Grande, mainly west of SA
  • WEDNESDAY: Line of storms Wednesday night, some strong, heavy rain approaching San Antonio
  • THURSDAY: Storms continue, heavy rain, flood threat
  • FRIDAY: Rain chances linger, cooler

FORECAST

TODAY

We are now just a few days away from changes, however, today will still be hot. Expect a high in the mid-90s, with a heat index near 100°.

TUESDAY

San Antonio will see partly cloudy and hot conditions on Tuesday, too. But, as the remnants of Polo moves north, a line of storms may develop across West Texas. This line is forecast to reach the Rio Grande late Tuesday night into very early Wednesday and bring rain to areas west of SA. This line likely dies down before reaching San Antonio.

Future radar for WEDNESDAY (9/30) at 2am (Copyright KSAT-12 2026 - All Rights Reserved)

WEDNESDAY NIGHT -- ⚠ FLOODING POSSIBLE ⚠

By Wednesday evening, another line of storms will take shape along a slow-moving front and move east. This line will be capable of producing some strong storms, but the main threat will be heavy rainfall. As of now, this line of storms is forecast to reach San Antonio pre-dawn on Thursday.

Future radar for THURSDAY (10/1) at 2am (Copyright KSAT-12 2026 - All Rights Reserved)

THURSDAY -- ⚠ FLOODING POSSIBLE ⚠

Storms are forecast to continue through at least the first half of the day on Thursday. Should we see storms tracking over the same areas, flooding would be a concern. This is a timeframe we will watch closely.

Future radar for THURSDAY (10/1) at 12pm (Copyright KSAT-12 2026 - All Rights Reserved)
A moderate flash flood risk exists on THURSDAY (10/1) along I-35. (Copyright KSAT-12 2026 - All Rights Reserved)

FRIDAY AND BEYOND

Showers may linger into Friday and potentially the weekend. Clouds and rain chances will keep temperatures down.

Extended Forecast (Copyright KSAT-12 2026 - All Rights Reserved)

QUICK WEATHER LINKS