San Antonio, TX Climate & Monthly Averages
The climate of San Antonio
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.
Climate quick facts
- 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%
Temperatures through the year
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.
Rain, sun and snow
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.
How San Antonio compares
- 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.
Ranked against every city in our dataset, each measured on the same ten-year window.
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
Average high and low for each month, with the bar showing where it sits in San Antonio's year (left is the coldest night, right is the 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
Warmer places to go, by month: January · February · March · April · May · June · July · August · September · October · November · December
Seasons in San Antonio
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.
Climate questions, answered
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How warm is San Antonio on average?
Are nights cold in San Antonio?
What should I wear in San Antonio?
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.
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).
San Antonio temperature records (2015-2024)
Derived from ERA5 reanalysis data, 2015–2024. Official station records may differ. Need the precipitation in other units? The mm-to-inches rainfall converter handles it.