In September, San Antonio typically sees daytime highs of 16.6°C and overnight lows around 6.9°C. Compared to the annual average high of 18.7°C, September runs -2.1°C.
September in San Antonio averages a daytime high of 16.6°C and an overnight low of 6.9°C.
September runs -2.1°C compared to San Antonio's annual average high of 18.7°C, ranking #9 of 12 months by warmth.
Plan for daytime highs near 16.6°C and cooler evenings around 6.9°C.