Weather in San Antonio in September 2025
Average weather
Average temperature in San Antonio in September
Going from a maximum of +40°C during the day to a minimum of +21°C during the night, the temperature in September averages around +37°C.
The average maximum temperature goes down 16% by the end of the month, compared with the beginning of the month, from +38°C to +35°C.
Is San Antonio warm or cold in September?
San Antonio is typically hot in September.
Maximum temperatures go down compared to the previous month from +36°C to +33°C. The minimum temperature also goes down from +24°C to +22°C.
Make sure that you pack your summer linen and swimming costumes; it’s probably going to be hot.
Take a look at how September is compared to other months in San Antonio:
Climate in San Antonio in September
| August | September | October | ||||
|---|---|---|---|---|---|---|
| Avg. temperature | ||||||
| +36°C | +33°C | +28°C | ||||
| Min. temperature | ||||||
| +18°C | +9°C | -1°C | ||||
| Max. temperature | ||||||
| +43°C | +43°C | +36°C | ||||
| Rainfall | ||||||
| 55 mm | 91 mm | 87 mm | ||||
| Wind | ||||||
| 3 m/s | 3 m/s | 3 m/s | ||||
| Humidity | ||||||
| 65% | 68% | 70% | ||||
| Air pressure | ||||||
| 1013 HPa | 1013 HPa | 1015 HPa | ||||
| Sunny days | ||||||
| 10 | 10 | 11 | ||||
| Cloudy days | ||||||
| 8 | 5 | 8 | ||||
| Rainy days | ||||||
| 12 | 13 | 11 | ||||
| Snowy days | ||||||
| 0 | 0 | 0 | ||||
September often has better weather than August. It’s getting colder in September. From +36°C in the day, the average maximum temperature lowers to +33°C. Prepare for more rain. Average rainfall goes from 55 mm to 91 mm. Humidity rises from 65% to 68%. The average wind speed doesn’t change much during September, staying around 3 m/s. The amount of sunny days stay about the same, averaging 10 sunny days during the month.
October brings much the same weather, it remains good.
Wind
The average wind speed is 3 m/s getting up to 6 m/s which is a medium breeze. You can feel it, especially getting out of the water.
The average wind speed in San Antonio is gradually increasing during September, going from 3 m/s to 4 m/s over the course of the month.
Rain
How was the weather last September in San Antonio?
Climate Change over Years
The climate in San Antonio in September has not changed much over the last 43 years.
The average temperature was the lowest in 1983 (+25°C) and the highest in 2006 (+30°C). The driest year was 1996 with only 401 mm of rainfall, and the wettest year was 2007 with 1606 mm.
FAQ
Is September a good time to visit San Antonio?
Can you sunbathe in San Antonio in September?
Is San Antonio rainy in September?
Is it sunny in San Antonio in September?
Other cities in USA
Monthly weather in San Antonio
Source of the data
For this page, we’ve looked at the typical weather in San Antonio, based on historical hourly weather data from January 1, 1979, to December 31, 2022.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.