San Marcos weather in December: San Marcos, Texas: normal highs, lows, rain and records for December
San Marcos in December has a normal high of 64°F and a normal low of 41°F, a daily mean of 52°F, falling from 67°F on the 1st to 62°F by the 31st. Measurable precipitation falls on 8 days in a normal December, 2.41 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 18°C and low of 5°C, 61 mm of precipitation in December.
- 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 December?
The normal high is 64°F and the normal low 41°F, for a daily mean of 52.2°F. December is 7.7°F cooler than November and 1.6°F warmer than January. December is the 11th warmest month of the year in San Marcos and the 9th wettest. Across the month the normal high falls 5°F, from 67°F on December 1 to 62°F on December 31. From one year to the next December's mean temperature typically moves about 2.4°F either way (NOAA's standard deviation), so roughly two Decembers in three average between 50°F and 55°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 |
|---|---|---|---|---|
| December 1 | 67°F | 44°F | 23% | 11% |
| December 8 | 65°F | 42°F | 24% | 11% |
| December 15 | 64°F | 41°F | 25% | 12% |
| December 22 | 63°F | 40°F | 25% | 12% |
| December 31 | 62°F | 39°F | 25% | 13% |
Every day of December: normal high, low and chance of precipitation (warmest afternoon December 1, coldest night December 31)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| December 1 | 67°F | 44°F | 23% | 11% | 10 h 20 min |
| December 2 | 67°F | 44°F | 23% | 11% | 10 h 20 min |
| December 3 | 66°F | 43°F | 23% | 11% | 10 h 20 min |
| December 4 | 66°F | 43°F | 23% | 11% | 10 h 20 min |
| December 5 | 66°F | 43°F | 24% | 11% | 10 h 20 min |
| December 6 | 66°F | 43°F | 24% | 11% | 10 h 20 min |
| December 7 | 65°F | 42°F | 24% | 11% | 10 h 20 min |
| December 8 | 65°F | 42°F | 24% | 11% | 10 h 20 min |
| December 9 | 65°F | 42°F | 24% | 11% | 10 h 20 min |
| December 10 | 65°F | 42°F | 24% | 12% | 10 h 20 min |
| December 11 | 64°F | 42°F | 25% | 12% | 10 h 20 min |
| December 12 | 64°F | 41°F | 25% | 12% | 10 h 20 min |
| December 13 | 64°F | 41°F | 25% | 12% | 10 h 20 min |
| December 14 | 64°F | 41°F | 25% | 12% | 10 h 10 min |
| December 15 | 64°F | 41°F | 25% | 12% | 10 h 10 min |
| December 16 | 63°F | 41°F | 25% | 12% | 10 h 10 min |
| December 17 | 63°F | 40°F | 25% | 12% | 10 h 10 min |
| December 18 | 63°F | 40°F | 25% | 12% | 10 h 10 min |
| December 19 | 63°F | 40°F | 25% | 12% | 10 h 10 min |
| December 20 | 63°F | 40°F | 25% | 12% | 10 h 10 min |
| December 21 | 63°F | 40°F | 25% | 12% | 10 h 10 min |
| December 22 | 63°F | 40°F | 25% | 12% | 10 h 10 min |
| December 23 | 62°F | 40°F | 25% | 13% | 10 h 10 min |
| December 24 | 62°F | 39°F | 25% | 13% | 10 h 10 min |
| December 25 | 62°F | 39°F | 25% | 13% | 10 h 10 min |
| December 26 | 62°F | 39°F | 25% | 13% | 10 h 10 min |
| December 27 | 62°F | 39°F | 25% | 13% | 10 h 10 min |
| December 28 | 62°F | 39°F | 25% | 13% | 10 h 10 min |
| December 29 | 62°F | 39°F | 25% | 13% | 10 h 10 min |
| December 30 | 62°F | 39°F | 25% | 13% | 10 h 10 min |
| December 31 | 62°F | 39°F | 25% | 13% | 10 h 10 min |
- Normal high
- 64°FDecember average
- Normal low
- 41°FDecember average
- Precipitation
- 2.41 inmonth total
- Days with precipitation
- 80.01 inch or more
- Nights at 32°F or colder
- 6
- Daylight
- 10 h 20 min to 10 h 10 minDecember 1 to December 31
- Days at 70°F or more
- 11
- Days at 80°F or more
- 1
- Sunshine
- 71%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 December?
On a given December day the chance of 0.01 inch or more is 25% on average, highest around December 18 (25%). In all, 2.41 in falls on 8 days of a normal December, 1 of them with an inch or more.
In a normal December in San Marcos, 6 nights fall to freezing.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USC00417983.
What are the records for December in San Marcos?
The warmest December temperature on this station's record (since 1895) is 91°F, on December 11, 1987; the coldest is 4°F, on December 22, 1989. The wettest December brought 17.10 in (1913); the snowiest, 10.0 inches (1929).
The December mean against the 1991-2020 normal of 52.2°F: 2021 60.9°F (+8.7), 2022 52.9°F (+0.7), 2023 55.1°F (+2.9), 2024 58.3°F (+6.1), 2025 57.8°F (+5.6). 5 of 5 ran warmer than normal.
| December | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 60.9°F | +8.7°F | 2.45 in |
| 2022 | 52.9°F | +0.7°F | 0.64 in |
| 2023 | 55.1°F | +2.9°F | 1.32 in |
| 2024 | 58.3°F | +6.1°F | 1.98 in |
| 2025 | 57.8°F | +5.6°F | 0.67 in |
Source: records: ACIS, station USC00417983; recent months: ACIS, station USC00417983. Records and recent months use complete months only.
How does December in San Marcos compare across Texas?
Across the 321 places PlainClimate covers in Texas, December normal highs run from 49°F in Dumas to 74°F in Brownsville; San Marcos's is 64°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.