Climate averages 1991–2020
San Antonio weather
in May.
A hot, wet month: the 5th warmest and the wettest of the year.
Long-term climate patterns, not a forecast for a particular trip.
May is a hot month in San Antonio: daytime highs average 29.9°C and nights cool to about 19.9°C. By daytime temperature it is the 5th warmest of the 12 months.
Expect about 103 mm of rain on roughly 11 days, which makes May a wet month (the wettest month of the year). Daylight, from sunrise to sunset, lasts about 13 h 36 min on an average May day.
The nearest other city in this atlas is New Braunfels (47 km away). In May its highs average 29.4°C, about as warm as San Antonio, with 108 mm of rain.
Among the 498 cities listed in the United States, San Antonio ranks joint 34th of 498 for the warmest May highs and joint 374th of 498 for the driest May (rainfall, lowest first). The mean May high of those 498 cities is 23.8°C; San Antonio is 6.1°C warmer than that mean.
From May to June, average highs rise by 3.1°C to 33.0°C, and monthly rainfall falls from 103 mm to 69 mm.
The annual picture
May in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
San Antonio climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 16.9°C6.7°C | 6.7°C | 57 | 7.2 | 10.510 h |
| February | 19.3°C8.7°C | 8.7°C | 59 | 7.5 | 11.111 h |
| March | 22.8°C12.1°C | 12.1°C | 79 | 9.2 | 12.012 h |
| April | 26.6°C15.7°C | 15.7°C | 78 | 8.5 | 12.913 h |
| May, selected | 29.9°C19.9°C | 19.9°C | 103 | 11.2 | 13.614 h |
| June | 33.0°C23.1°C | 23.1°C | 69 | 9.5 | 14.014 h |
| July | 34.5°C24.1°C | 24.1°C | 50 | 6.1 | 13.814 h |
| August | 35.1°C24.7°C | 24.7°C | 50 | 5.8 | 13.213 h |
| September | 31.6°C22.0°C | 22.0°C | 77 | 8.6 | 12.412 h |
| October | 27.3°C17.3°C | 17.3°C | 83 | 7.7 | 11.511 h |
| November | 21.5°C11.7°C | 11.7°C | 67 | 7.2 | 10.711 h |
| December | 17.5°C7.8°C | 7.8°C | 63 | 7.5 | 10.310 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
May in nearby cities
- New Braunfels in MayUnited States · 47 kmHigh 29.4°C · Low 19.7°C · 108 mm rain
- Austin in MayUnited States · 118 kmHigh 29.3°C · Low 19.5°C · 116 mm rain
- Round Rock in MayUnited States · 144 kmHigh 28.9°C · Low 19.3°C · 110 mm rain
- Killeen in MayUnited States · 202 kmHigh 28.5°C · Low 18.8°C · 115 mm rain
- Corpus Christi in MayUnited States · 210 kmHigh 29.4°C · Low 22.5°C · 71 mm rain
- Piedras Negras in MayMexico · 213 kmHigh 32.9°C · Low 21.8°C · 74 mm rain
- Temple in MayUnited States · 216 kmHigh 28.3°C · Low 18.8°C · 123 mm rain
- Ciudad Acuña in MayMexico · 238 kmHigh 32.3°C · Low 21.3°C · 64 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for San Antonio) is explained once on the San Antonio year overview and on the Sources, method and limits page.