San Antonio
Texas, USA
Long-term weather forecast
Long-term weather forecast

September weather forecast and Climate
San Antonio, TX

Buildings in San Antonio, Texas, with a calm view of the bridges across the waterfront
Buildings in San Antonio, Texas, with a calm view of the bridges across the waterfront
September sees a gradual drop in temperatures with the start of the fall season in San Antonio. The first half of the month has daily highs of 90°F (32.2°C), while the latter half drops to 80°F (26.7°C). Low temperatures dip to 65°F (18.3°C) in the night with the advent of the autumn.
By the end of September, the fall season starts to display various shades of colors. The summer crowds dwindle with the end of school vacations, and San Antonio becomes more relaxed and spacious.
  • The average high temperature in September: 90°F

Warmest months (with the highest average high temperature) are July and August (95°F).
The month with the lowest average high temperature is January (61°F).

  • The average low temperature in September: 70°F

Months with the highest average low temperature are July and August (73°F).
The coldest month (with the lowest average low temperature) is January (37°F).

  • The average rainfall in September: 3.5"

The wettest month (with the highest rainfall) is May (3.7").
Driest months (with the lowest rainfall) are January, March, July and December (1.5").

  • The average rainfall days in September: 7 days

The month with the highest number of rainy days is May (8 days).
Months with the lowest number of rainy days are July and August (5 days).

  • The average daylight in September: 12h

Months with the longest days are May, June and July (Average daylight: 14h).
The month with shortest days is December (Average daylight: 10h).

  • The average sunshine in September: 8h

The month with most sunshine is July (Average sunshine: 10h).
Months with least sunshine are January and December (Average sunshine: 5).

  • The average UV index in September: 10

Months with the highest UV index are May, June, July and August (UV index 11).
Months with the lowest UV index are January and December (UV index 4).