San Antonio weather in August
In August, San Antonio has daytime highs averaging 35 °C, nights around 25 °C, with 5.7 wet days. Figures are 1991–2020 climate normals.
- 35.2°C Average high
- 24.7°C Average low
- 5.7days Wet days
- 50mm Rainfall
- 13h Daylight
Daily temperatures through August
How August develops
Averages for the first, middle and last part of the month, from daily 1991–2020 normals. Chance of rain is the share of years in which that calendar day recorded more than 1 mm.
| Days | Avg high | Avg low | Chance of rain |
|---|---|---|---|
| 1–10 August | 35.5 °C | 24.6 °C | 12 % |
| 11–20 August | 35.7 °C | 24.9 °C | 17 % |
| 21–31 August | 34.5 °C | 24.5 °C | 26 % |
- Average highs fall from 35.5 °C early in August to 34.5 °C by the end of it.
- Rain is most likely over days 21–31 of August (26 % of days) and least likely over days 1–10 (12 %).
What to expect
| Measure | Typical August | Share of the month |
|---|---|---|
| Days above 25 °C | 31 of 31 | 100 % |
| Days above 30 °C | 30 of 31 | 96 % |
| Days below 0 °C | 0 of 31 | 0 % |
| Days with more than 1 mm rain | 5.7 of 31 | 18 % |
Conditions in August
| Measure | Average |
|---|---|
| Mean temperature | 29 °C |
| Record high (1991–2020) | 43 °C |
| Record low (1991–2020) | 19 °C |
| Relative humidity | 62 % |
| Wind speed | 17 km/h |
| Cloud cover | 42 % |
Where San Antonio ranks in August
| Ranking | Position | Value |
|---|---|---|
| The warmest places in North America in August | 18thof 50 | 35 °C |
August compared with the months around it
| Month | Avg high | Rainfall | Cloud |
|---|---|---|---|
| June | 33.1 °C | 72 mm | 47 % |
| July | 34.6 °C | 53 mm | 45 % |
| August | 35.2 °C | 50 mm | 42 % |
| September | 31.8 °C | 84 mm | 44 % |
| October | 27.7 °C | 84 mm | 41 % |
See all twelve months for San Antonio
- August is the warmest month in San Antonio.
- It is the 1st driest month of the year.
- It ranks 2nd for least cloud cover.
- Days last about 13 hours from sunrise to sunset.
- It rains on 5.7 of 31 days — 18 % of the month.
- Nights are about 11 °C cooler than the middle of the day.
- The hottest August day on record since 1991 reached 43 °C, 7.9 °C above the usual daytime high.
Nearby destinations in August
| Destination | Avg high | Wet days |
|---|---|---|
| San Antonio | 35 °C | 5.7 |
| Austin | 35 °C | 5 |
| Corpus Christi | 32 °C | 9 |
| Piedras Negras | 37 °C | 4 |
| Nuevo Laredo | 37 °C | 5 |
| Ciudad Acuña | 36 °C | 4 |
| Cypress | 34 °C | 11 |
| Houston | 33 °C | 14 |
QuestionsAugust in San Antonio, answered
How warm is San Antonio in August?
Daily highs average 35 °C and nights fall to about 25 °C, a spread of 11 °C between afternoon and dawn. That makes August the 1st warmest month of the year here.
Does it rain much in San Antonio in August?
August averages 50 mm of rain, spread over about 6 of the 31 days — 18 % of the month. Cloud cover averages 42 % of the sky.
How long are the days in August?
San Antonio averages 13 hours between sunrise and sunset in August. Day length is computed from latitude and date, so it is exact rather than modelled — but it says nothing about how much of that time is sunny.
Data sources and method
- ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
- Open-Meteo — Open-Meteo.com. CC BY 4.0
- NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
- GeoNames — GeoNames.org. CC BY 4.0
- Normal period
- 1991–2020
- Dataset version
- era5-1991-2020-scores1.1
- Last processed
Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: daylight hours, beach and comfort scores, monthly rankings, threshold day counts, chance of a wet day by date, ten-day averages within the month. Full formulas are on the methodology page.
Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.