January is one of the cooler months of the year in San Antonio, with average highs near 16.8°C and lows around 4.2°C (mean 10.5°C). It is one of the drier months, averaging 47 mm of rainfall and 70% relative humidity across the period.
January is one of the cooler months of the year in San Antonio. Across 45 years of records, the warmest January in San Antonio was 2006 — when the month averaged 14.8°C — while the coldest was 1985 at 6.1°C. Typical January days reach 16.8°C with nights near 4.2°C. The long-term trend is warming, about 0.3°C per decade.
January is one of the drier months in San Antonio, averaging 47 mm of rainfall. The wettest January on record was 1991 with 132 mm, while the driest was 2014 at 5 mm.
Relative humidity in San Antonio during January averages 70%. The most humid January was 1992 at 82%, and the least humid was 2006 at 49%.
January receives about 3 kWh/m²/day of solar energy in San Antonio. The sunniest January was 2006 at 3.7 kWh/m²/day, and the cloudiest was 1993 at 2.3.
Average wind speed in San Antonio during January is 2.7 m/s. The windiest Januarys were 1982 and 1996 at 3.1 m/s, while the calmest were 1981, 1992 and 2016 at 2.3 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 9.4°C | 10.6°C | 11.3°C | 10.2°C | 11.4°C | +2°C |
| Avg High | 15.6°C | 16.9°C | 17.5°C | 16.6°C | 18.1°C | +2.5°C |
| Avg Low | 3.2°C | 4.3°C | 5.1°C | 3.8°C | 4.7°C | +1.5°C |
| Avg Rain | 42 mm | 52 mm | 47 mm | 52 mm | 42 mm | +1 mm |
January temperatures in San Antonio have risen by about 2°C between 1981–1985 and 2021–2025.
January has ranged from a record low of -9.2°C (1982) to a record high of 29.3°C (1989).
Rainfall in January is one of the drier months, averaging 47 mm, with a wettest year of 132 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.5°C per decade while lows rose 0.2°C per decade, widening the gap between day and night.
A quieter season to visit San Antonio
If your dates are flexible, the more temperate months of April and October tend to be the most comfortable for visiting San Antonio. That said, January — with days averaging 16.8°C and nights around 4.2°C (mean 10.5°C) and moderate rainfall (47 mm) — can still be rewarding for travellers who don't mind the cooler conditions, and often means fewer crowds.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 15.8°C | 9.2°C | 2.6°C | 24.7°C | -6.0°C | 33 mm | 62% | 2.9 m/s | 2.9 |
| 2024 | 15.7°C | 9.3°C | 3.0°C | 22.5°C | -6.8°C | 105 mm | 67% | 2.7 m/s | 3.2 |
| 2023 | 20.7°C | 13.8°C | 6.9°C | 27.0°C | -0.2°C | 30 mm | 64% | 2.7 m/s | 3.3 |
| 2022 | 17.4°C | 10.4°C | 3.5°C | 27.5°C | -2.2°C | 16 mm | 56% | 2.7 m/s | 3.3 |
| 2021 | 18.6°C | 11.5°C | 4.4°C | 26.5°C | -2.2°C | 24 mm | 68% | 2.7 m/s | 3.3 |
| 2020 | 20.2°C | 14.0°C | 7.7°C | 27.3°C | 1.4°C | 46 mm | 69% | 2.6 m/s | 3.1 |
| 2019 | 16.3°C | 10.5°C | 4.6°C | 24.2°C | -1.1°C | 42 mm | 76% | 2.5 m/s | 3 |
| 2018 | 15.8°C | 9.1°C | 2.4°C | 22.8°C | -6.0°C | 7 mm | 64% | 2.5 m/s | 3.1 |
| 2017 | 19.2°C | 12.9°C | 6.5°C | 25.0°C | -6.6°C | 54 mm | 70% | 3 m/s | 3.4 |
| 2016 | 16.5°C | 10.1°C | 3.6°C | 26.9°C | -1.8°C | 31 mm | 75% | 2.3 m/s | 3.5 |
| 2015 | 14.5°C | 8.7°C | 2.9°C | 26.1°C | -3.8°C | 71 mm | 73% | 2.6 m/s | 2.8 |
| 2014 | 16.1°C | 8.8°C | 1.6°C | 24.7°C | -4.8°C | 5 mm | 63% | 2.9 m/s | 3.5 |
| 2013 | 17.6°C | 11.4°C | 5.2°C | 27.7°C | -3.6°C | 73 mm | 71% | 2.8 m/s | 3.1 |
| 2012 | 19.2°C | 12.1°C | 5.0°C | 25.1°C | -0.7°C | 78 mm | 69% | 2.7 m/s | 3.3 |
| 2011 | 16.6°C | 9.9°C | 3.2°C | 25.3°C | -3.6°C | 70 mm | 67% | 2.5 m/s | 3.1 |
| 2010 | 14.0°C | 8.3°C | 2.5°C | 23.2°C | -5.5°C | 86 mm | 78% | 2.8 m/s | 3 |
| 2009 | 19.8°C | 12.3°C | 4.9°C | 28.0°C | -1.2°C | 8 mm | 52% | 2.7 m/s | 3.5 |
| 2008 | 17.0°C | 10.4°C | 3.9°C | 26.4°C | -4.3°C | 16 mm | 63% | 2.8 m/s | 2.9 |
| 2007 | 13.2°C | 8.0°C | 2.8°C | 23.3°C | -2.7°C | 130 mm | 79% | 2.8 m/s | 2.5 |
| 2006 🔥 | 22.1°C | 14.8°C | 7.4°C | 29.0°C | 2.5°C | 15 mm | 49% | 3 m/s | 3.7 |
| 2005 | 17.2°C | 12.0°C | 6.8°C | 24.6°C | -2.3°C | 60 mm | 80% | 2.8 m/s | 2.6 |
| 2004 | 17.7°C | 12.2°C | 6.7°C | 25.7°C | -1.9°C | 72 mm | 73% | 2.7 m/s | 2.6 |
| 2003 | 14.7°C | 9.0°C | 3.2°C | 24.7°C | -4.5°C | 30 mm | 79% | 2.5 m/s | 3.1 |
| 2002 | 17.8°C | 11.4°C | 5.0°C | 25.6°C | -4.1°C | 20 mm | 74% | 2.8 m/s | 3.1 |
| 2001 | 15.0°C | 9.5°C | 4.0°C | 22.4°C | -3.3°C | 68 mm | 79% | 2.7 m/s | 2.8 |
| 2000 | 20.5°C | 13.3°C | 6.0°C | 29.0°C | -4.0°C | 47 mm | 65% | 2.8 m/s | 3.1 |
| 1999 | 18.5°C | 11.6°C | 4.6°C | 25.4°C | -5.4°C | 10 mm | 74% | 2.8 m/s | 3.5 |
| 1998 | 19.4°C | 13.0°C | 6.7°C | 23.5°C | 1.3°C | 83 mm | 78% | 2.7 m/s | 2.9 |
| 1997 | 14.9°C | 8.9°C | 2.9°C | 28.8°C | -4.6°C | 25 mm | 70% | 2.8 m/s | 2.7 |
| 1996 | 17.8°C | 10.0°C | 2.3°C | 25.9°C | -5.9°C | 6 mm | 60% | 3.1 m/s | 3.6 |
| 1995 | 17.3°C | 10.8°C | 4.4°C | 23.9°C | -4.2°C | 17 mm | 72% | 2.6 m/s | 3.3 |
| 1994 | 17.4°C | 11.1°C | 4.8°C | 27.8°C | -2.6°C | 41 mm | 71% | 2.9 m/s | 2.8 |
| 1993 | 15.7°C | 9.8°C | 3.9°C | 24.1°C | -1.3°C | 50 mm | 78% | 2.4 m/s | 2.3 |
| 1992 | 13.7°C | 9.1°C | 4.5°C | 20.5°C | -4.1°C | 126 mm | 82% | 2.3 m/s | 2.7 |
| 1991 🌧️ | 14.7°C | 8.9°C | 3.1°C | 23.0°C | -2.7°C | 132 mm | 78% | 2.5 m/s | 2.7 |
| 1990 | 19.3°C | 12.8°C | 6.2°C | 25.1°C | 0.1°C | 35 mm | 65% | 2.7 m/s | 2.9 |
| 1989 | 19.1°C | 12.9°C | 6.8°C | 29.3°C | -2.6°C | 94 mm | 70% | 2.9 m/s | 2.5 |
| 1988 | 14.3°C | 8.0°C | 1.6°C | 23.7°C | -5.6°C | 10 mm | 69% | 2.9 m/s | 3 |
| 1987 | 14.8°C | 9.0°C | 3.3°C | 22.0°C | -3.9°C | 28 mm | 79% | 2.7 m/s | 3.3 |
| 1986 | 17.0°C | 10.5°C | 4.0°C | 23.1°C | -1.0°C | 30 mm | 73% | 2.6 m/s | 3.4 |
| 1985 ❄️ | 12.0°C | 6.1°C | 0.2°C | 23.4°C | -8.4°C | 62 mm | 74% | 2.7 m/s | 2.8 |
| 1984 | 13.7°C | 7.9°C | 2.1°C | 23.2°C | -6.8°C | 54 mm | 70% | 2.7 m/s | 2.9 |
| 1983 | 15.9°C | 9.4°C | 2.9°C | 23.9°C | -2.7°C | 31 mm | 74% | 2.4 m/s | — |
| 1982 | 17.5°C | 10.4°C | 3.3°C | 26.1°C | -9.2°C | 21 mm | 64% | 3.1 m/s | — |
| 1981 | 15.9°C | 10.0°C | 4.2°C | 24.0°C | -1.9°C | 47 mm | 72% | 2.3 m/s | — |
Actual recorded January data for each year, 1981–2025 — sourced from NASA POWER.
The average high in January is around 16.8°C with lows near 4.2°C (mean 10.5°C), based on 45 years of NASA POWER data.
January averages 47 mm of rainfall in San Antonio, one of the drier months. The wettest on record was 132 mm in 1991.
The hottest January reached 29.3°C in 1989. The coldest dipped to -9.2°C in 1982.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average January temperatures have risen by about 2°C. Daytime highs moved from 15°C to 17.6°C and overnight lows from 2.5°C to 4.1°C over the same span.
January is one of the cooler months of the year in San Antonio and one of the drier months, so plan for around 16.8°C daytime highs and 4.2°C at night.
Yes — January is the coldest month of the year in San Antonio, averaging 10.5°C.
For January in San Antonio, pack warm layers and a jacket for chilly mornings, with typical highs of 16.8°C and lows of 4.2°C.
Relative humidity in January averages 70% — moderately humid.
Average wind speed in January is 2.7 m/s. The windiest January on record averaged 3.1 m/s (1982).
The wettest January on record was 1991 with 132 mm. On average, January sees 47 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in San Antonio behaves each January, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for January specifically, along with year-by-year records and how the month has changed over the decades.
