San Antonio Weather in August

The hot weather for San Antonio, Texas peaks in August. This is also one of the city's sunniest months.

This page gives detailed information on the typical August temperature, precipitation, sun, humidity, wind and storms for San Antonio. The numbers here are historical averages based on climate data gathered at the San Antonio International Airport, located a few miles north of the city center.

Temperature Weather iconTemperature

96 °F August average high 36 °C
75 °F August average low 24 °C

August is San Antonio's hottest month overall, with temperatures peaking from the 2nd to 11th. These dates have daily highs averaging 97 degrees Fahrenheit (36 degrees Celsius) and lows of 76 °F (24 °C).

29 days 90 °F max. or more (32 °C)
2 days 70 °F min. or less (21 °C)

Usually every August day is over 80 °F (27 °C) at San Antonio. The city averages 9 days this month when the thermometer reaches into the 100s °F (over 38 °C).

August does not normally cool down as far as 60 °F (16 °C) at night.

Rainy Weather iconRain

2.2 in total precipitation 55 mm
5 days of rain

Half the time, San Antonio receives 0.4 to 2.8 inches (9 to 70 mm) of rainfall in August. One in four years has drier weather, while another one in four is wetter.

Sunny Weather iconSun

74 % sunshine
10 days clear skies

August is one of the sunniest months for San Antonio. The sun's rays reach the ground during 74 percent of daylight hours on average, for a monthly total of 302 hours. Typically on 10 days this month the sky is mainly clear, with at most 30 percent cloud cover.

Sunlight in August at San Antonio lasts for 13 hours and 9 minutes a day on average. The longest day of the month is the 1st with 13 hours and 32 minutes of daylight. By the end of the month, the days have shortened to 12:46 from sunrise to sunset. These durations can vary by a minute or two from year to year.

Humid Weather iconHumidity

65 % August average humidity

The relative humidity in San Antonio during August usually peaks at 86 percent in the morning then drops to 44 percent by mid afternoon.

Local Time12 am3 am6 am9 am12 pm3 pm6 pm9 pm
Humidity % 74 82 86 72 53 44 46 61

Windy Weather iconWind

8.4 mph August wind speed average 13.5 kph

August is less windy than most other months in San Antonio.

Stormy Weather iconStorms

1 day rainfall of 0.5 inches (13 mm) or more
4 days with thunderstorms in August
6 % chance a named storm approaches

There's a 2 percent probability that a hurricane will approach within 100 miles (165 km) of San Antonio during August. The chance of a major hurricane (category 3 to 5) reaching the area is 1 percent.


The weather data here are long-term averages provided by the US National Centers for Environmental Information (NCEI). Temperature and precipitation are 1991-2020 normals while humidity and thunderstorms are 1961-1990 normals. The named storm probabilities come from the Atlantic Oceanographic and Meteorological Laboratory, Hurricane Research Division.

San Antonio Weather
Back to Top