San Antonio Weather in May
Average highs run from 22°C on May 1 to 17°C on May 31, and lows from 10°C to 8°C. Normal precipitation for the month is 62 mm over about 6 wet days.
May day by day
The normal high and low for each date, in °C.
- Normal low
- Normal high
- Reanalysis extreme high
- Reanalysis extreme low
May at a glance
- Average high
- 19°C
- Average low
- 9°C
- Precipitation
- 62 mm
- Reanalysis high
- 32°CMay 25, 2020
- Reanalysis low
- 2°CMay 24, 1993
- Daylight
- 10 h 45 min to 10 h 04 min
- Cloud cover
- 61%
- Humidity
- 66%
- Dew point
- 6°C
- Wind
- 8.6 km/h
Every day of the month
A wet day has at least 1 mm of precipitation in the reanalysis.
| Date | Normal high | Normal low | Reanalysis high | Reanalysis low | Chance wet |
|---|---|---|---|---|---|
| May 1 | 22°C | 10°C | 28°C 2019 | 5°C 1992 | 12% |
| May 2 | 22°C | 10°C | 30°C 2003 | 6°C 2000 | 12% |
| May 3 | 22°C | 10°C | 29°C 1997 | 6°C 2015 | 13% |
| May 4 | 21°C | 10°C | 29°C 1994 | 6°C 1991 | 13% |
| May 5 | 21°C | 10°C | 27°C 2003 | 7°C 2005 | 13% |
| May 6 | 21°C | 10°C | 30°C 2020 | 6°C 2005 | 13% |
| May 7 | 21°C | 10°C | 27°C 2020 | 6°C 2005 | 13% |
| May 8 | 21°C | 10°C | 26°C 2010 | 8°C 1993 | 14% |
| May 9 | 21°C | 10°C | 27°C 2010 | 6°C 2012 | 14% |
| May 10 | 20°C | 10°C | 30°C 1996 | 6°C 2000 | 14% |
| May 11 | 20°C | 9°C | 26°C 2018 | 5°C 2003 | 15% |
| May 12 | 20°C | 9°C | 26°C 1994 | 5°C 1993 | 15% |
| May 13 | 20°C | 9°C | 26°C 1994 | 6°C 1995 | 16% |
| May 14 | 20°C | 9°C | 25°C 2019 | 4°C 2013 | 16% |
| May 15 | 19°C | 9°C | 27°C 2020 | 3°C 2013 | 17% |
| May 16 | 19°C | 9°C | 26°C 2020 | 5°C 2005 | 18% |
| May 17 | 19°C | 9°C | 30°C 2020 | 4°C 2007 | 18% |
| May 18 | 19°C | 9°C | 27°C 1995 | 6°C 2005 | 19% |
| May 19 | 19°C | 9°C | 26°C 2018 | 5°C 2017 | 20% |
| May 20 | 19°C | 9°C | 24°C 2018 | 4°C 2005 | 22% |
| May 21 | 18°C | 9°C | 26°C 2009 | 3°C 2019 | 23% |
| May 22 | 18°C | 9°C | 24°C 2009 | 4°C 1996 | 23% |
| May 23 | 18°C | 9°C | 26°C 2020 | 3°C 1993 | 24% |
| May 24 | 18°C | 9°C | 30°C 2020 | 2°C 1993 | 25% |
| May 25 | 18°C | 9°C | 32°C 2020 | 3°C 1993 | 24% |
| May 26 | 18°C | 9°C | 25°C 2020 | 4°C 1992 | 24% |
| May 27 | 18°C | 8°C | 25°C 2014 | 5°C 1992 | 24% |
| May 28 | 18°C | 8°C | 22°C 2012 | 4°C 1992 | 25% |
| May 29 | 18°C | 8°C | 24°C 1995 | 4°C 2008 | 25% |
| May 30 | 17°C | 8°C | 24°C 1999 | 4°C 1992 | 25% |
| May 31 | 17°C | 8°C | 25°C 2011 | 3°C 1993 | 25% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (GMT-4).
- May 1
- sunrise 7:21 AM, sunset 6:06 PM
- May 31
- sunrise 7:42 AM, sunset 5:46 PM
Other months
Sources
Cloud, humidity, wind and sunshine, and temperature and precipitation: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-25. Sun and moon: computed with the NOAA solar equations and Meeus.