San Antonio weather in September
Temperature, rain and sunshine in September: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in September
Fair
Best time to visit: October – April
What is the weather like in San Antonio in September?
In September, San Antonio is hot: daytime highs average 32 °C, and even at night it stays warm at around 22 °C. The sun shines for around 7 hours a day. Rain falls on about 7 days, adding up to 70 mm. On about 22 days the thermometer climbs to 30 °C or more. The air is often humid and muggy. All in all, September is a so-so month for a holiday in San Antonio.
September compared
How the weather changes from August to October. Tap a month to open it.
| AugustAug | SeptemberSep | OctoberOct | |
|---|---|---|---|
| Score | 45 | 55 | 81 |
| Day | 35° | 32° | 28° |
| Night | 25° | 22° | 18° |
| Sun | 9 h | 7 h | 6 h |
| Rain days | 6 | 7 | 7 |
More details for September
- Daylight
- 12 h 23 min07:18 – 19:41
- UV index
- 9 · very highclear sky, noon (estimate)All months
- Muggy days
- 21 daysdew point 18 °C or moreAll months
- Wind
- 16 km/haverage daily peakAll months
- Cloud cover
- 43 %on averageAll months
- Hot days
- 22 days30 °C or moreAll months
- Time zone
- UTC−5America/Chicago
How the score comes together
- Temperatureweight 50 %38 %
- Sunshineweight 20 %67 %
- Few rainy daysweight 30 %76 %
Each factor is rated from 0 to 100 % and weighted for the travel style “City break”.
What to pack in September
- Sunscreen
- Sunglasses & sun hat
- Light, breathable clothes
- Water bottle – drink plenty
- Insect repellent
San Antonio in September: quick answers
Is San Antonio hot in September?
Yes. In September, San Antonio is hot: daytime highs average 32 °C and nights stay around 22 °C. On about 22 days the thermometer climbs to 30 °C or more.
Does it rain much in San Antonio in September?
Rain falls on about 7 days, adding up to 70 mm.
San Antonio month by month
The whole year in San AntonioAll destinations: USAWhere to go in September
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences