San Antonio weather in May: San Antonio, Texas: normal highs, lows, rain and records for May
San Antonio in May has a normal high of 87°F and a normal low of 66°F, a daily mean of 77°F, rising from 83°F on the 1st to 90°F by the 31st. Measurable precipitation falls on 8 days in a normal May, 4.40 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 30°C and low of 19°C, 112 mm of precipitation in May.
- NOAA stationSan Antonio International Airport
- Station IDUSW00012921
- Location29.54°N 98.48°W
- Elevation789 ft (241 m)
- From the center6 miles
- Population1,526,656
- Jan 63° 41°
- Feb 68° 45°
- Mar 74° 52°
- Apr 80° 58°
- May 87° 66°
- Jun 92° 73°
- Jul 95° 75°
- Aug 96° 75°
- Sep 90° 70°
- Oct 82° 60°
- Nov 72° 50°
- Dec 65° 42°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is San Antonio in May?
The normal high is 87°F and the normal low 66°F, for a daily mean of 76.5°F. May is 7.1°F warmer than April and 6.1°F cooler than June. May is the 5th warmest month of the year in San Antonio and the wettest. Across the month the normal high rises 7°F, from 83°F on May 1 to 90°F on May 31. From one year to the next May's mean temperature typically moves about 2.2°F either way (NOAA's standard deviation), so roughly two Mays in three average between 74°F and 79°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 26%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| May 1 | 83°F | 62°F | 24% | 14% |
| May 8 | 85°F | 64°F | 25% | 15% |
| May 15 | 86°F | 66°F | 26% | 16% |
| May 22 | 88°F | 68°F | 26% | 16% |
| May 31 | 90°F | 70°F | 25% | 16% |
Every day of May: normal high, low and chance of precipitation (warmest afternoon May 31, coldest night May 1)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| May 1 | 83°F | 62°F | 24% | 14% | 13 h 20 min |
| May 2 | 83°F | 62°F | 24% | 14% | 13 h 20 min |
| May 3 | 83°F | 63°F | 24% | 14% | 13 h 20 min |
| May 4 | 84°F | 63°F | 25% | 15% | 13 h 20 min |
| May 5 | 84°F | 63°F | 25% | 15% | 13 h 20 min |
| May 6 | 84°F | 64°F | 25% | 15% | 13 h 20 min |
| May 7 | 84°F | 64°F | 25% | 15% | 13 h 30 min |
| May 8 | 85°F | 64°F | 25% | 15% | 13 h 30 min |
| May 9 | 85°F | 64°F | 25% | 15% | 13 h 30 min |
| May 10 | 85°F | 65°F | 25% | 16% | 13 h 30 min |
| May 11 | 85°F | 65°F | 26% | 16% | 13 h 30 min |
| May 12 | 86°F | 65°F | 26% | 16% | 13 h 30 min |
| May 13 | 86°F | 66°F | 26% | 16% | 13 h 30 min |
| May 14 | 86°F | 66°F | 26% | 16% | 13 h 40 min |
| May 15 | 86°F | 66°F | 26% | 16% | 13 h 40 min |
| May 16 | 87°F | 67°F | 26% | 16% | 13 h 40 min |
| May 17 | 87°F | 67°F | 26% | 16% | 13 h 40 min |
| May 18 | 87°F | 67°F | 26% | 16% | 13 h 40 min |
| May 19 | 87°F | 67°F | 26% | 16% | 13 h 40 min |
| May 20 | 88°F | 68°F | 26% | 16% | 13 h 40 min |
| May 21 | 88°F | 68°F | 26% | 16% | 13 h 40 min |
| May 22 | 88°F | 68°F | 26% | 16% | 13 h 40 min |
| May 23 | 88°F | 68°F | 26% | 16% | 13 h 50 min |
| May 24 | 89°F | 69°F | 26% | 16% | 13 h 50 min |
| May 25 | 89°F | 69°F | 26% | 16% | 13 h 50 min |
| May 26 | 89°F | 69°F | 26% | 16% | 13 h 50 min |
| May 27 | 89°F | 70°F | 26% | 16% | 13 h 50 min |
| May 28 | 90°F | 70°F | 26% | 16% | 13 h 50 min |
| May 29 | 90°F | 70°F | 25% | 16% | 13 h 50 min |
| May 30 | 90°F | 70°F | 25% | 16% | 13 h 50 min |
| May 31 | 90°F | 70°F | 25% | 16% | 13 h 50 min |
- Normal high
- 87°FMay average
- Normal low
- 66°FMay average
- Precipitation
- 4.40 inmonth total
- Days with precipitation
- 80.01 inch or more
- Days at 90°F or more
- 12
- Daylight
- 13 h 20 min to 13 h 50 minMay 1 to May 31
- Days at 70°F or more
- 31
- Days at 80°F or more
- 28
- Sunshine
- 76%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00012921; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in San Antonio in May?
On a given May day the chance of 0.01 inch or more is 25% on average, highest around May 16 (26%). In all, 4.40 in falls on 8 days of a normal May, 2 of them with an inch or more.
In a normal May in San Antonio, 12 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00012921.
How humid and windy is San Antonio in May?
At 3 p.m. the normal temperature is 89°F with 48% relative humidity and a dew point of 67°F; at 6 a.m. it is 72°F with 87% humidity. The wind averages 9.3 mph, most often from the southeast in the afternoon. A dew point of 65°F or more feels muggy to most people.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 72°F | 68°F | 87% | 6.7 mph | 14% |
| 9 a.m. | 78°F | 69°F | 72% | 9.1 mph | 20% |
| noon | 85°F | 68°F | 56% | 9.6 mph | 27% |
| 3 p.m. | 89°F | 67°F | 48% | 10.7 mph | 34% |
| 6 p.m. | 87°F | 66°F | 50% | 11.4 mph | 36% |
| 9 p.m. | 80°F | 68°F | 67% | 10.6 mph | 42% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00012921. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for May in San Antonio?
The warmest May temperature on San Antonio's official record (since 1885) is 104°F, on May 31, 2004; the coldest is 42°F, on May 4, 2013. The wettest May brought 14.07 in (1935).
The May mean against the 1991-2020 normal of 76.5°F: 2021 75.5°F (−1.0), 2022 83.0°F (+6.5), 2023 76.2°F (−0.3), 2024 81.5°F (+5.0), 2025 80.5°F (+4.0), 2026 75.1°F (−1.4). 3 of 6 ran warmer than normal.
| May | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 75.5°F | −1.0°F | 6.14 in |
| 2022 | 83.0°F | +6.5°F | 0.86 in |
| 2023 | 76.2°F | −0.3°F | 3.92 in |
| 2024 | 81.5°F | +5.0°F | 0.97 in |
| 2025 | 80.5°F | +4.0°F | 5.98 in |
| 2026 | 75.1°F | −1.4°F | 5.81 in |
Source: records: ACIS, NWS threaded record SATthr; recent months: ACIS, station USW00012921. Records and recent months use complete months only.
How does May in San Antonio compare across Texas?
Across the 321 places PlainClimate covers in Texas, May normal highs run from 78°F in Hartley to 98°F in Terlingua; San Antonio's is 87°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.