August is one of the warmer months of the year in San Antonio, with average highs near 36.1°C and lows around 23.7°C (mean 29.9°C). It is about average for rainfall, averaging 57 mm of rainfall and 60% relative humidity across the period.
August is one of the warmer months of the year in San Antonio. Across 45 years of records, the warmest August in San Antonio was 2023 — when the month averaged 32.9°C — while the coldest was 2007 at 26.8°C. Typical August days reach 36.1°C with nights near 23.7°C. The long-term trend is warming, about 0.4°C per decade.
August is about average for rainfall in San Antonio, averaging 57 mm of rainfall. The wettest August on record was 2016 with 207 mm, while the driest was 2011 at 3 mm.
Relative humidity in San Antonio during August averages 60%. The most humid August was 2007 at 83%, and the least humid were 2011 and 2023 at 47%.
August receives about 6.4 kWh/m²/day of solar energy in San Antonio. The sunniest Augusts were 1985, 2011 and 2023 at 7 kWh/m²/day, and the cloudiest were 1998 and 2008 at 5.7.
Average wind speed in San Antonio during August is 2.6 m/s. The windiest August was 1993 at 3.3 m/s, while the calmest were 2003, 2008 and 2025, among others at 2.2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 29.8°C | 29.2°C | 29.2°C | 30.7°C | 31.2°C | +1.4°C |
| Avg High | 36.2°C | 35.2°C | 34.9°C | 37.2°C | 37.7°C | +1.5°C |
| Avg Low | 23.3°C | 23.2°C | 23.6°C | 24.2°C | 24.6°C | +1.3°C |
| Avg Rain | 42 mm | 74 mm | 66 mm | 56 mm | 41 mm | -1 mm |
August temperatures in San Antonio have risen by about 1.4°C between 1981–1985 and 2021–2025.
August has ranged from a record low of 17.7°C (1989) to a record high of 44.5°C (2011).
Rainfall in August is about average for rainfall, averaging 57 mm, with a wettest year of 207 mm.
A quieter season to visit San Antonio
If your dates are flexible, the more temperate months of April and October tend to be the most comfortable for visiting San Antonio. That said, August — with days averaging 36.1°C and nights around 23.7°C (mean 29.9°C) and moderate rainfall (57 mm) — can still be rewarding for travellers who don't mind the warmth, and often means fewer crowds.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 38.9°C | 31.9°C | 24.8°C | 40.7°C | 22.7°C | 31 mm | 51% | 2.2 m/s | 6.4 |
| 2024 | 38.4°C | 31.7°C | 25.0°C | 43.9°C | 23.0°C | 28 mm | 56% | 2.3 m/s | 6.8 |
| 2023 🔥 | 40.4°C | 32.9°C | 25.4°C | 43.3°C | 23.4°C | 19 mm | 47% | 2.8 m/s | 7 |
| 2022 | 36.0°C | 30.4°C | 24.7°C | 40.1°C | 23.7°C | 74 mm | 64% | 2.6 m/s | 5.8 |
| 2021 | 34.3°C | 28.9°C | 23.5°C | 37.4°C | 22.4°C | 67 mm | 71% | 2.4 m/s | 6.3 |
| 2020 | 38.2°C | 31.2°C | 24.1°C | 41.6°C | 21.2°C | 28 mm | 55% | 2.7 m/s | 6.8 |
| 2019 | 39.3°C | 32.4°C | 25.6°C | 41.8°C | 24.2°C | 9 mm | 52% | 2.9 m/s | 6.7 |
| 2018 | 36.8°C | 30.3°C | 23.9°C | 38.6°C | 21.0°C | 42 mm | 59% | 2.9 m/s | 6.6 |
| 2017 | 34.9°C | 29.2°C | 23.5°C | 38.9°C | 18.2°C | 189 mm | 65% | 3.2 m/s | 6.1 |
| 2016 🌧️ | 32.4°C | 27.9°C | 23.3°C | 38.5°C | 21.9°C | 207 mm | 76% | 2.4 m/s | 5.8 |
| 2015 | 38.0°C | 31.1°C | 24.2°C | 42.0°C | 20.6°C | 16 mm | 54% | 2.6 m/s | 6.7 |
| 2014 | 37.8°C | 31.0°C | 24.2°C | 40.1°C | 22.1°C | 16 mm | 53% | 3 m/s | 6.7 |
| 2013 | 37.4°C | 30.6°C | 23.8°C | 40.9°C | 21.5°C | 17 mm | 54% | 2.6 m/s | 6.6 |
| 2012 | 37.4°C | 30.6°C | 23.8°C | 41.1°C | 21.4°C | 50 mm | 56% | 2.7 m/s | 6.8 |
| 2011 | 39.8°C | 32.7°C | 25.5°C | 44.5°C | 24.2°C | 3 mm | 47% | 2.9 m/s | 7 |
| 2010 | 37.8°C | 31.2°C | 24.6°C | 41.5°C | 20.8°C | 9 mm | 54% | 2.7 m/s | 6.8 |
| 2009 | 37.6°C | 31.0°C | 24.4°C | 40.0°C | 21.4°C | 23 mm | 52% | 2.9 m/s | 6.7 |
| 2008 | 33.3°C | 28.2°C | 23.1°C | 39.5°C | 20.8°C | 118 mm | 71% | 2.2 m/s | 5.7 |
| 2007 ❄️ | 30.6°C | 26.8°C | 23.1°C | 34.1°C | 21.7°C | 128 mm | 83% | 2.3 m/s | 6 |
| 2006 | 36.2°C | 30.4°C | 24.6°C | 39.3°C | 22.6°C | 14 mm | 58% | 2.8 m/s | 6.4 |
| 2005 | 35.3°C | 29.5°C | 23.7°C | 39.4°C | 20.1°C | 45 mm | 64% | 2.5 m/s | 6.3 |
| 2004 | 34.4°C | 28.5°C | 22.6°C | 38.3°C | 18.4°C | 60 mm | 66% | 2.3 m/s | 6.2 |
| 2003 | 35.0°C | 29.1°C | 23.1°C | 41.6°C | 20.0°C | 43 mm | 65% | 2.2 m/s | 6.3 |
| 2002 | 33.0°C | 27.9°C | 22.8°C | 37.9°C | 20.9°C | 40 mm | 75% | 2.4 m/s | 6.4 |
| 2001 | 36.1°C | 30.3°C | 24.5°C | 41.0°C | 21.6°C | 180 mm | 59% | 2.9 m/s | 6.2 |
| 2000 | 37.0°C | 30.4°C | 23.7°C | 40.9°C | 22.2°C | 11 mm | 54% | 2.8 m/s | 6.7 |
| 1999 | 37.2°C | 30.8°C | 24.4°C | 41.5°C | 22.9°C | 25 mm | 55% | 2.5 m/s | 6.6 |
| 1998 | 33.3°C | 28.3°C | 23.4°C | 40.2°C | 21.0°C | 201 mm | 72% | 2.2 m/s | 5.7 |
| 1997 | 36.8°C | 30.0°C | 23.3°C | 39.9°C | 20.2°C | 42 mm | 58% | 2.7 m/s | 6.5 |
| 1996 | 33.3°C | 28.3°C | 23.2°C | 40.5°C | 20.7°C | 157 mm | 68% | 2.7 m/s | 5.9 |
| 1995 | 35.0°C | 29.5°C | 24.0°C | 38.1°C | 22.6°C | 65 mm | 65% | 2.3 m/s | 6.2 |
| 1994 | 34.6°C | 28.7°C | 22.8°C | 37.8°C | 20.9°C | 82 mm | 65% | 2.5 m/s | 6.2 |
| 1993 | 37.4°C | 30.7°C | 24.0°C | 39.9°C | 22.4°C | 12 mm | 54% | 3.3 m/s | 6.8 |
| 1992 | 33.9°C | 27.6°C | 21.3°C | 36.2°C | 17.7°C | 61 mm | 64% | 2.3 m/s | 6.4 |
| 1991 | 35.9°C | 29.6°C | 23.3°C | 39.7°C | 22.1°C | 56 mm | 60% | 2.4 m/s | 6.3 |
| 1990 | 34.4°C | 28.2°C | 22.1°C | 38.7°C | 19.3°C | 36 mm | 66% | 2.6 m/s | 6.7 |
| 1989 | 36.0°C | 29.4°C | 22.8°C | 38.5°C | 17.7°C | 27 mm | 58% | 3.1 m/s | 6.2 |
| 1988 | 36.8°C | 30.4°C | 24.1°C | 40.2°C | 21.8°C | 21 mm | 56% | 2.5 m/s | 6.2 |
| 1987 | 36.1°C | 29.6°C | 23.2°C | 39.7°C | 21.0°C | 46 mm | 62% | 2.9 m/s | 6.6 |
| 1986 | 36.0°C | 29.6°C | 23.2°C | 42.5°C | 18.6°C | 42 mm | 57% | 2.9 m/s | 6.2 |
| 1985 | 38.1°C | 31.0°C | 23.9°C | 40.3°C | 21.5°C | 10 mm | 50% | 2.9 m/s | 7 |
| 1984 | 36.0°C | 29.5°C | 22.9°C | 39.7°C | 20.2°C | 29 mm | 56% | 2.9 m/s | 6.5 |
| 1983 | 34.3°C | 28.6°C | 22.9°C | 39.0°C | 21.7°C | 67 mm | 67% | 2.2 m/s | — |
| 1982 | 37.2°C | 30.5°C | 23.8°C | 39.8°C | 21.7°C | 34 mm | 55% | 3 m/s | — |
| 1981 | 35.5°C | 29.3°C | 23.1°C | 39.2°C | 19.2°C | 106 mm | 62% | 2.6 m/s | — |
Actual recorded August data for each year, 1981–2025 — sourced from NASA POWER.
The average high in August is around 36.1°C with lows near 23.7°C (mean 29.9°C), based on 45 years of NASA POWER data.
August averages 57 mm of rainfall in San Antonio, about average for rainfall. The wettest on record was 207 mm in 2016.
The hottest August reached 44.5°C in 2011. The coldest dipped to 17.7°C in 1989.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average August temperatures have risen by about 1.4°C. Daytime highs moved from 36.2°C to 37.6°C and overnight lows from 23.3°C to 24.7°C over the same span.
August is one of the warmer months of the year in San Antonio and about average for rainfall, so plan for around 36.1°C daytime highs and 23.7°C at night.
Not quite — August is the 12th coolest month in San Antonio, averaging 29.9°C.
For August in San Antonio, pack light, breathable clothing and sun protection, with typical highs of 36.1°C and lows of 23.7°C. Bring an umbrella or light rain jacket too.
Relative humidity in August averages 60% — moderately humid.
Average wind speed in August is 2.6 m/s. The windiest August on record averaged 3.3 m/s (1993).
The wettest August on record was 2016 with 207 mm. On average, August sees 57 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in San Antonio behaves each August, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for August specifically, along with year-by-year records and how the month has changed over the decades.
