San Marcos weather by month
What a typical year looks like in San Marcos, Texas: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at SAN MARCOS, 2 km from San Marcos; records cover 1895–2026.
The year at a glance
- Precipitation a year
- 36.6 in928 mm
- Snow a year
- Rare
- Last spring freeze
- Feb 24
- First fall freeze
- Nov 29
- Heating degree days
- 1,620
- Cooling degree days
- 2,974
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are 26°−3° (heating, 99%) and 103°39° (cooling, 1%).
Month by month
San Marcos in January
Highs average 62°17° and lows 39°4°, with 2.4 in61 mm of precipitation in a typical January.
- Record high
- 89°32° (1918)
- Record low
- −2°−19° (1949)
- Heating degree days
- 452
- Cooling degree days
- 6
San Marcos in February
Highs average 67°19° and lows 42°6°, with 1.7 in44 mm of precipitation in a typical February.
- Record high
- 99°37° (1996)
- Record low
- 5°−15° (1951)
- Heating degree days
- 308
- Cooling degree days
- 14
San Marcos in March
Highs average 73°23° and lows 50°10°, with 2.8 in70 mm of precipitation in a typical March.
- Record high
- 100°38° (1925)
- Record low
- 17°−8° (1980)
- Heating degree days
- 167
- Cooling degree days
- 52
San Marcos in April
Highs average 80°27° and lows 56°13°, with 3.2 in81 mm of precipitation in a typical April.
- Record high
- 102°39° (1920)
- Record low
- 30°−1° (1920)
- Heating degree days
- 43
- Cooling degree days
- 135
San Marcos in May
Highs average 86°30° and lows 65°18°, with 4.5 in115 mm of precipitation in a typical May.
- Record high
- 106°41° (1925)
- Record low
- 40°4° (1908)
- Heating degree days
- 4
- Cooling degree days
- 331
San Marcos in June
Highs average 92°34° and lows 72°22°, with 3.6 in91 mm of precipitation in a typical June.
- Record high
- 109°43° (1998)
- Record low
- 51°11° (1903)
- Heating degree days
- 0
- Cooling degree days
- 511
San Marcos in July
Highs average 96°35° and lows 73°23°, with 2.2 in56 mm of precipitation in a typical July.
- Record high
- 110°43° (1954)
- Record low
- 56°13° (1967)
- Heating degree days
- 0
- Cooling degree days
- 606
San Marcos in August
Highs average 97°36° and lows 74°23°, with 2.6 in66 mm of precipitation in a typical August.
- Record high
- 111°44° (1917)
- Record low
- 50°10° (2010)
- Heating degree days
- 0
- Cooling degree days
- 628
San Marcos in September
Highs average 91°33° and lows 69°20°, with 4 in102 mm of precipitation in a typical September.
- Record high
- 111°44° (2000)
- Record low
- 39°4° (2010)
- Heating degree days
- 1
- Cooling degree days
- 436
San Marcos in OctoberThis month
Highs average 82°28° and lows 58°15°, with 4.4 in112 mm of precipitation in a typical October.
- Record high
- 101°38° (1924)
- Record low
- 27°−3° (1917)
- Heating degree days
- 41
- Cooling degree days
- 199
San Marcos in November
Highs average 72°22° and lows 48°9°, with 2.7 in68 mm of precipitation in a typical November.
- Record high
- 98°37° (1934)
- Record low
- 17°−8° (1911)
- Heating degree days
- 199
- Cooling degree days
- 46
San Marcos in December
Highs average 64°18° and lows 41°5°, with 2.4 in61 mm of precipitation in a typical December.
- Record high
- 91°33° (1987)
- Record low
- 4°−16° (1989)
- Heating degree days
- 405
- Cooling degree days
- 10