San Antonio is warmest in August, averaging 38° by day and 24° at night. The wettest month is May with 105 mm, and the year brings about 585 mm in total.
Month by month
| Month | High | Low | Rain | Daylight | Good for |
|---|---|---|---|---|---|
| January | 19° | 4° | 43 mm | 10.3 h | Sightseeing |
| February | 19° | 7° | 25 mm | 11.0 h | Sightseeing |
| March | 26° | 11° | 34 mm | 11.8 h | Beach weather |
| April | 30° | 15° | 66 mm | 12.7 h | Beach weather |
| May | 32° | 19° | 105 mm | 13.5 h | Beach weather |
| June | 36° | 22° | 48 mm | 13.9 h | Beach weather |
| July | 37° | 24° | 53 mm | 13.7 h | Very hot |
| August | 38° | 24° | 43 mm | 13.1 h | Very hot |
| September | 35° | 21° | 48 mm | 12.2 h | Beach weather |
| October | 31° | 16° | 47 mm | 11.3 h | Beach weather |
| November | 24° | 10° | 45 mm | 10.5 h | Sightseeing |
| December | 21° | 6° | 28 mm | 10.1 h | Sightseeing |
High and low are average daily maximum and minimum, rain is typical monthly total, daylight is the hours between sunrise and sunset mid-month. Climate normals from NASA POWER — averages, not promises.
When to go
Beach weather: March, April, May, June, September and October — highs around 32°, nights no colder than 11°, and at most 105 mm of rain in a month.
Walking the city: January, February, November and December — highs of 19–24° and no more than 45 mm of rain a month.
Serious heat: In July and August the average high reaches 38°.