San Antonio, TX Climate & Monthly Averages
San Antonio has a humid subtropical climate. August is the hottest month, averaging 96° by day; January is the coldest at 63°.
Sunshine is a defining feature of San Antonio's climate
Expect hot, humid summers and generally mild winters in San Antonio: that is what a humid subtropical climate means in practice. Highs peak at 96°F (36°C) in August and fall to 63°F (17°C) by January, with 9.1 hours of sun on an average day.
How sun, temperature and rain fit together
Warmth peaks in August: highs of 96°F (36°C), lows of 77°F (25°C). January is the coolest month, with highs of 63°F (17°C) and lows near 44°F (7°C). The gridded 2015-2024 daily record for this location tops out at 107°F (42°C) and bottoms at 8°F (-13°C) - decade extremes, not all-time station records. Snowfall is rare but not unheard of.
Days and nights are about 10°C apart on average - wider than roughly 78% of the cities we track. Four of the twelve months pair mild highs with fewer than twelve wet days; the longest unbroken run is February through March. The wettest month is May (6.8 inches (172 mm) across 16 days) and the driest February. Relative humidity averages 67% across the year, drier than about 75% of the cities we track.
More climate facts for San Antonio
- Hottest month: August - highs near 96°F (36°C)
- Coldest month: January - highs near 63°F (17°C)
- Decade extremes (2015-2024): 107°F (42°C) high · 8°F (-13°C) low
- Wettest month: May (16 rainy days) · Sunniest: July (12.0 h sun/day)
- Climate type: humid subtropical
- Annual swing: 18°C between the average warmest and coolest month · day to night: 10°C
- Months averaging 30°C or hotter: 5
- Average humidity: 67%
The most comfortable sunny-weather window
Best time to visit San Antonio
Aim for January to April and October to November if you get the choice: warm days, manageable rainfall and plenty of daylight line up, and highs average 74°F (23°C) against roughly 9 wet days a month. For the same question asked the other way round, see where else is warm in January.
What to pack
Pack for San Antonio with lightweight, breathable clothing and serious sun protection and a compact umbrella or rain shell. Note the gap between afternoon and night: August pairs 96°F (36°C) with 77°F (25°C).
Monthly climate table
| Month | High | Low | Rain days | Precipitation | Sunshine | Daylight | Wet-day chance | Humidity |
|---|---|---|---|---|---|---|---|---|
| January | 63° | 44° | 8 | 2.2 in | 7.4 h/day | 10.4 h | 25% | 65% |
| February | 67° | 47° | 8 | 2.1 in | 7.0 h/day | 11.1 h | 28% | 67% |
| March | 76° | 56° | 10 | 2.5 in | 7.8 h/day | 11.9 h | 33% | 66% |
| April | 81° | 61° | 12 | 4.1 in | 8.8 h/day | 12.8 h | 39% | 67% |
| May | 86° | 69° | 16 | 6.8 in | 9.6 h/day | 13.6 h | 51% | 74% |
| June | 93° | 74° | 11 | 2.9 in | 11.6 h/day | 14.0 h | 36% | 69% |
| July | 96° | 76° | 7 | 2.6 in | 12.0 h/day | 13.9 h | 23% | 64% |
| August | 96° | 77° | 7 | 3.1 in | 11.6 h/day | 13.2 h | 24% | 62% |
| September | 91° | 73° | 10 | 4.0 in | 10.3 h/day | 12.3 h | 32% | 66% |
| October | 83° | 64° | 8 | 3.8 in | 9.2 h/day | 11.4 h | 26% | 63% |
| November | 71° | 54° | 9 | 2.8 in | 7.0 h/day | 10.6 h | 30% | 70% |
| December | 66° | 48° | 8 | 2.3 in | 6.7 h/day | 10.3 h | 26% | 69% |
San Antonio month by month
Each card shows the average high and low. The bar places that month between San Antonio's coldest night and warmest afternoon.
January
- Rain
- 8 days
- Sunshine
- 7.4 h
- Daylight
- 10.4 h
February
- Rain
- 8 days
- Sunshine
- 7.0 h
- Daylight
- 11.1 h
March
- Rain
- 10 days
- Sunshine
- 7.8 h
- Daylight
- 11.9 h
April
- Rain
- 12 days
- Sunshine
- 8.8 h
- Daylight
- 12.8 h
May
- Rain
- 16 days
- Sunshine
- 9.6 h
- Daylight
- 13.6 h
June
- Rain
- 11 days
- Sunshine
- 11.6 h
- Daylight
- 14.0 h
July
- Rain
- 7 days
- Sunshine
- 12.0 h
- Daylight
- 13.9 h
August
- Rain
- 7 days
- Sunshine
- 11.6 h
- Daylight
- 13.2 h
September
- Rain
- 10 days
- Sunshine
- 10.3 h
- Daylight
- 12.3 h
October
- Rain
- 8 days
- Sunshine
- 9.2 h
- Daylight
- 11.4 h
November
- Rain
- 9 days
- Sunshine
- 7.0 h
- Daylight
- 10.6 h
December
- Rain
- 8 days
- Sunshine
- 6.7 h
- Daylight
- 10.3 h
Looking for warmer alternatives? Browse warm places by month, or compare San Antonio's coolest part of the year: January, December, February.
Seasonal weather under San Antonio's sunnier skies
Spring (March through May)
Through spring, San Antonio runs hot: 81°F (27°C) by day, 62°F (17°C) after dark, and rain falls on around 38 of the 90 days.
Summer (June through August)
Summer turns very hot here - highs near 95°F (35°C), nights near 76°F (24°C), and expect showers on roughly 25 days across the season. Daylight is generous - around 11.7 hours of sun a day.
Fall (September through November)
Through fall, San Antonio sits firmly in the heat: 82°F (28°C) by day, 64°F (18°C) after dark, and expect showers on roughly 27 days across the season.
Winter (December through February)
Winter in San Antonio stays on the cool side of mild, with daytime highs averaging 66°F (19°C) and nights around 46°F (8°C); expect showers on roughly 24 days across the season.
How unusual is San Antonio?
- San Antonio sits close to the middle of our dataset on most measures: 71°F (22°C) as an annual average, 39.1 inches (994 mm) of precipitation and 9.1 hours of sun a day.
These comparisons use the same ten-year window for every city in the dataset.
San Antonio temperature extremes in the 2015–2024 dataset
Derived from ERA5 reanalysis data, 2015–2024. Official station records may differ. Need another precipitation unit? Use the rainfall converter.