San Marcos weather in May: San Marcos, Texas: normal highs, lows, rain and records for May
San Marcos in May has a normal high of 86°F and a normal low of 65°F, a daily mean of 76°F, rising from 83°F on the 1st to 90°F by the 31st. Measurable precipitation falls on 8 days in a normal May, 4.53 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 30°C and low of 18°C, 115 mm of precipitation in May.
- NOAA stationSan Marcos
- Station IDUSC00417983
- Location29.88°N 97.95°W
- Elevation665 ft (203 m)
- Population74,316
- Jan 62° 39°
- Feb 67° 42°
- Mar 73° 50°
- Apr 80° 56°
- May 86° 65°
- Jun 92° 72°
- Jul 96° 73°
- Aug 97° 74°
- Sep 91° 69°
- Oct 82° 58°
- Nov 72° 48°
- Dec 64° 41°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is San Marcos in May?
The normal high is 86°F and the normal low 65°F, for a daily mean of 75.5°F. May is 7.5°F warmer than April and 6.6°F cooler than June. May is the 5th warmest month of the year in San Marcos 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 73°F and 78°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 25%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| May 1 | 83°F | 60°F | 22% | 15% |
| May 8 | 84°F | 62°F | 24% | 17% |
| May 15 | 86°F | 65°F | 25% | 18% |
| May 22 | 88°F | 67°F | 25% | 18% |
| May 31 | 90°F | 69°F | 24% | 18% |
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 | 60°F | 22% | 15% | 13 h 20 min |
| May 2 | 83°F | 60°F | 23% | 15% | 13 h 20 min |
| May 3 | 83°F | 61°F | 23% | 16% | 13 h 20 min |
| May 4 | 83°F | 61°F | 23% | 16% | 13 h 20 min |
| May 5 | 84°F | 61°F | 23% | 16% | 13 h 20 min |
| May 6 | 84°F | 62°F | 23% | 16% | 13 h 30 min |
| May 7 | 84°F | 62°F | 23% | 16% | 13 h 30 min |
| May 8 | 84°F | 62°F | 24% | 17% | 13 h 30 min |
| May 9 | 84°F | 63°F | 24% | 17% | 13 h 30 min |
| May 10 | 85°F | 63°F | 24% | 17% | 13 h 30 min |
| May 11 | 85°F | 63°F | 24% | 17% | 13 h 30 min |
| May 12 | 85°F | 64°F | 24% | 17% | 13 h 30 min |
| May 13 | 85°F | 64°F | 24% | 18% | 13 h 40 min |
| May 14 | 86°F | 64°F | 24% | 18% | 13 h 40 min |
| May 15 | 86°F | 65°F | 25% | 18% | 13 h 40 min |
| May 16 | 86°F | 65°F | 25% | 18% | 13 h 40 min |
| May 17 | 86°F | 65°F | 25% | 18% | 13 h 40 min |
| May 18 | 87°F | 66°F | 25% | 18% | 13 h 40 min |
| May 19 | 87°F | 66°F | 25% | 18% | 13 h 40 min |
| May 20 | 87°F | 66°F | 25% | 18% | 13 h 40 min |
| May 21 | 88°F | 67°F | 25% | 18% | 13 h 50 min |
| May 22 | 88°F | 67°F | 25% | 18% | 13 h 50 min |
| May 23 | 88°F | 67°F | 24% | 18% | 13 h 50 min |
| May 24 | 88°F | 68°F | 24% | 18% | 13 h 50 min |
| May 25 | 89°F | 68°F | 24% | 18% | 13 h 50 min |
| May 26 | 89°F | 68°F | 24% | 18% | 13 h 50 min |
| May 27 | 89°F | 68°F | 24% | 18% | 13 h 50 min |
| May 28 | 89°F | 69°F | 24% | 18% | 13 h 50 min |
| May 29 | 90°F | 69°F | 24% | 18% | 13 h 50 min |
| May 30 | 90°F | 69°F | 24% | 18% | 13 h 50 min |
| May 31 | 90°F | 69°F | 24% | 18% | 13 h 50 min |
- Normal high
- 86°FMay average
- Normal low
- 65°FMay average
- Precipitation
- 4.53 inmonth total
- Days with precipitation
- 80.01 inch or more
- Days at 90°F or more
- 10
- 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
- 27
- Sunshine
- 78%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USC00417983; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in San Marcos in May?
On a given May day the chance of 0.01 inch or more is 24% on average, highest around May 18 (25%). In all, 4.53 in falls on 8 days of a normal May, 2 of them with an inch or more.
In a normal May in San Marcos, 10 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USC00417983.
What are the records for May in San Marcos?
The warmest May temperature on this station's record (since 1895) is 106°F, on May 24, 1925; the coldest is 40°F, on May 1, 1908. The wettest May brought 14.35 in (1929).
The May mean against the 1991-2020 normal of 75.5°F: 2021 73.4°F (−2.1), 2022 81.3°F (+5.8), 2023 75.1°F (−0.4), 2024 78.9°F (+3.4), 2025 79.3°F (+3.8), 2026 74.8°F (−0.7). 3 of 6 ran warmer than normal.
| May | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 73.4°F | −2.1°F | 8.48 in |
| 2022 | 81.3°F | +5.8°F | 1.87 in |
| 2023 | 75.1°F | −0.4°F | 3.56 in |
| 2024 | 78.9°F | +3.4°F | 5.12 in |
| 2025 | 79.3°F | +3.8°F | 5.89 in |
| 2026 | 74.8°F | −0.7°F | 5.08 in |
Source: records: ACIS, station USC00417983; recent months: ACIS, station USC00417983. Records and recent months use complete months only.
How does May in San Marcos 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 Marcos's is 86°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.