San Antonio weather in May
In May, San Antonio has an average high of 32 °C89 °F and an average low of 19 °C67 °F, with about 100 mm3.9 in of precipitation. It is the 5th warmest month of the year and the wettest.
How May compares with other months
Compared with April, May is 3.8 °C6.9 °F warmer on average and wetter by 37 mm1.5 in. Compared with June, May is 3.3 °C5.9 °F cooler on average and wetter by 29 mm1.1 in. Daylight lasts about 13.6 hours around the middle of the month. Average relative humidity is 68% and the average cloud amount 60%.
Is May a good time to visit San Antonio?
May is not among the most comfortable months by our comfort score: it is hot (average high 32 °C89 °F) and it is fairly wet (100 mm3.9 in). The most comfortable months in San Antonio are February–April and October–December.
What to wear in May
For San Antonio in May, pack very light, breathable clothing, a sun hat and plenty of water and an umbrella or light rain jacket.
May in nearby places
| Place | High °C°F | Low °C°F | Precip. mmin |
|---|---|---|---|
| San Antonio | 3289 | 1967 | 1003.9 |
| Austin | 3187 | 1965 | 1114.4 |
| Killeen | 3085 | 1864 | 1094.3 |
| Corpus Christi | 3188 | 2171 | 803.1 |
| Piedras Negras | 3595 | 2169 | 752.9 |
| Ciudad Acuña | 3595 | 2169 | 572.3 |
| Nuevo Laredo | 3595 | 2170 | 682.7 |
| College Station | 3086 | 1865 | 1194.7 |
| Waco | 2985 | 1864 | 1134.5 |
Nearby places that are more than 1 °C1.8 °F warmer in May: Piedras Negras, Ciudad Acuña and Nuevo Laredo; cooler: Austin, Killeen, College Station and Waco.
Other months in San Antonio
- January17 °C63 °F / 5 °C40 °F
- February20 °C68 °F / 6 °C44 °F
- March24 °C76 °F / 11 °C51 °F
- April29 °C84 °F / 15 °C59 °F
- May32 °C89 °F / 19 °C67 °F
- June35 °C95 °F / 23 °C73 °F
- July36 °C96 °F / 24 °C75 °F
- August36 °C97 °F / 24 °C76 °F
- September32 °C90 °F / 21 °C70 °F
- October28 °C83 °F / 16 °C60 °F
- November23 °C73 °F / 10 °C50 °F
- December18 °C64 °F / 5 °C42 °F
Frequently asked questions
How warm is San Antonio in May?
In May the average high in San Antonio is 32 °C (89 °F) and the average low is 19 °C (67 °F).
Does it rain a lot in San Antonio in May?
On average about 100 mm (3.9 in) of precipitation falls in May; it ranks 1st of the 12 months.
Is May the warmest month in San Antonio?
No. The warmest month in San Antonio is August, with an average high of 36 °C (97 °F). The coldest month is January, with an average low of 5 °C (40 °F).
How long is the day in San Antonio in May?
In the middle of May the day in San Antonio lasts about 13.6 hours from sunrise to sunset. The value is calculated from the position of the city and the sun.
How humid is San Antonio in May?
The average relative humidity in May is about 68%. This is a long-term average for the whole day.
How cloudy is San Antonio in May?
On average about 60% of the sky is covered by cloud in May. This is the mean cloud amount from satellite data, not the number of sunny days.
About this data
All figures are 25-year averages (January 2001 – December 2025) from the NASA POWER project. Temperature, humidity, wind and precipitation come from the MERRA-2 reanalysis (precipitation is the bias-corrected MERRA-2 product), cloud and solar values from CERES satellite data. They describe a grid cell of roughly 50–70 km, not a single weather station, so they can differ from airport records — most of all on coasts, in mountains and for rainfall. Average highs and lows are the monthly mean temperature plus/minus half of the average daily temperature range. Counts of rainy days are not part of this dataset.
The grid cell’s average elevation is 302 m, while San Antonio lies at about 198 m. Temperatures on this page were therefore adjusted by +0.7 °C1.2 °F using the standard lapse rate of 6.5 °C per 1,000 m.