San Antonio weather in January
In January, San Antonio has an average high of 17 °C63 °F and an average low of 5 °C40 °F, with about 49 mm1.9 in of precipitation. January is the coldest month of the year and ranks 10th for precipitation.
How January compares with other months
Compared with December, January is 1 °C1.7 °F cooler on average. Compared with February, January is 2.3 °C4.2 °F cooler on average and wetter by 13 mm0.5 in. Daylight lasts about 10.4 hours around the middle of the month. Average relative humidity is 70% and the average cloud amount 55%.
Is January a good time to visit San Antonio?
January is not among the most comfortable months by our comfort score: it is cool (average high 17 °C63 °F) and nights are cold (average low 5 °C40 °F). The most comfortable months in San Antonio are February–April and October–December.
What to wear in January
For San Antonio in January, pack long sleeves, a sweater and a medium jacket and an extra layer for the cooler mornings and evenings.
January in nearby places
| Place | High °C°F | Low °C°F | Precip. mmin |
|---|---|---|---|
| San Antonio | 1763 | 540 | 491.9 |
| Austin | 1660 | 338 | 582.3 |
| Killeen | 1559 | 236 | 562.2 |
| Corpus Christi | 1967 | 947 | 401.6 |
| Piedras Negras | 1967 | 642 | 160.6 |
| Ciudad Acuña | 1966 | 541 | 150.6 |
| Nuevo Laredo | 2068 | 745 | 240.9 |
| College Station | 1559 | 338 | 783.1 |
| Waco | 1458 | 236 | 662.6 |
Nearby places that are more than 1 °C1.8 °F warmer in January: Corpus Christi, Piedras Negras, Ciudad Acuña and Nuevo Laredo; cooler: Austin, Killeen, College Station and Waco.
Other months in San Antonio
- January17 °C63 °F / 5 °C40 °F
- February20 °C68 °F / 6 °C44 °F
- March24 °C76 °F / 11 °C51 °F
- April29 °C84 °F / 15 °C59 °F
- May32 °C89 °F / 19 °C67 °F
- June35 °C95 °F / 23 °C73 °F
- July36 °C96 °F / 24 °C75 °F
- August36 °C97 °F / 24 °C76 °F
- September32 °C90 °F / 21 °C70 °F
- October28 °C83 °F / 16 °C60 °F
- November23 °C73 °F / 10 °C50 °F
- December18 °C64 °F / 5 °C42 °F
Frequently asked questions
How warm is San Antonio in January?
In January the average high in San Antonio is 17 °C (63 °F) and the average low is 5 °C (40 °F).
Does it rain a lot in San Antonio in January?
On average about 49 mm (1.9 in) of precipitation falls in January; it ranks 10th of the 12 months.
Is January the warmest month in San Antonio?
No. The warmest month in San Antonio is August, with an average high of 36 °C (97 °F). The coldest month is January, with an average low of 5 °C (40 °F).
How long is the day in San Antonio in January?
In the middle of January the day in San Antonio lasts about 10.4 hours from sunrise to sunset. The value is calculated from the position of the city and the sun.
How humid is San Antonio in January?
The average relative humidity in January is about 70%. This is a long-term average for the whole day.
How cloudy is San Antonio in January?
On average about 55% of the sky is covered by cloud in January. This is the mean cloud amount from satellite data, not the number of sunny days.
About this data
All figures are 25-year averages (January 2001 – December 2025) from the NASA POWER project. Temperature, humidity, wind and precipitation come from the MERRA-2 reanalysis (precipitation is the bias-corrected MERRA-2 product), cloud and solar values from CERES satellite data. They describe a grid cell of roughly 50–70 km, not a single weather station, so they can differ from airport records — most of all on coasts, in mountains and for rainfall. Average highs and lows are the monthly mean temperature plus/minus half of the average daily temperature range. Counts of rainy days are not part of this dataset.
The grid cell’s average elevation is 302 m, while San Antonio lies at about 198 m. Temperatures on this page were therefore adjusted by +0.7 °C1.2 °F using the standard lapse rate of 6.5 °C per 1,000 m.