January is one of the cooler months of the year in Decatur, with average highs near 0.8°C and lows around -8.3°C (mean -3.8°C). It is one of the drier months, averaging 53 mm of rainfall and 85% relative humidity across the period.
January is one of the cooler months of the year in Decatur. Across 45 years of records, the warmest January in Decatur was 2006 — when the month averaged 2.9°C — while the coldest was 1982 at -11.6°C. Typical January days reach 0.8°C with nights near -8.3°C. The long-term trend is warming, about 0.6°C per decade.
January is one of the drier months in Decatur, averaging 53 mm of rainfall. The wettest January on record was 2005 with 157 mm, while the driest was 1986 at 2 mm.
Relative humidity in Decatur during January averages 85%. The most humid January was 1982 at 94%, and the least humid was 2003 at 76%.
January receives about 1.9 kWh/m²/day of solar energy in Decatur. The sunniest Januarys were 2002, 2022 and 2025, among others at 2.2 kWh/m²/day, and the cloudiest was 2017 at 1.4.
Average wind speed in Decatur during January is 3.9 m/s. The windiest Januarys were 2008 and 2014 at 4.8 m/s, while the calmest was 1998 at 3.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | -5.4°C | -3.9°C | -2.8°C | -3.7°C | -2.7°C | +2.7°C |
| Avg High | -0.6°C | 0.6°C | 1.7°C | 0.7°C | 1.6°C | +2.2°C |
| Avg Low | -10.3°C | -8.4°C | -7.2°C | -8.1°C | -6.9°C | +3.4°C |
| Avg Rain | 33 mm | 63 mm | 61 mm | 44 mm | 66 mm | +33 mm |
January temperatures in Decatur have risen by about 3.9°C between 1981–1985 and 2021–2025.
January has ranged from a record low of -35.9°C (1982) to a record high of 20.4°C (1997).
Rainfall in January is one of the drier months, averaging 53 mm, with a wettest year of 157 mm.
A quieter season to visit Decatur
If your dates are flexible, the more temperate months of June and August tend to be the most comfortable for visiting Decatur. That said, January — with days averaging 0.8°C and nights around -8.3°C (mean -3.8°C) and moderate rainfall (53 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 | -0.4°C | -5.0°C | -9.6°C | 8.2°C | -21.4°C | 23 mm | 79% | 3.8 m/s | 2.2 |
| 2024 | -0.5°C | -4.2°C | -7.8°C | 6.8°C | -27.2°C | 125 mm | 89% | 3.5 m/s | 1.5 |
| 2023 | 4.8°C | 0.7°C | -3.3°C | 19.1°C | -14.6°C | 57 mm | 85% | 3.6 m/s | 1.5 |
| 2022 | -0.2°C | -5.3°C | -10.5°C | 7.3°C | -19.0°C | 16 mm | 81% | 4 m/s | 2.2 |
| 2021 | 2.1°C | -1.8°C | -5.7°C | 8.5°C | -12.8°C | 60 mm | 86% | 3.4 m/s | 1.7 |
| 2020 | 3.7°C | -0.4°C | -4.5°C | 15.0°C | -15.7°C | 117 mm | 86% | 3.5 m/s | 1.6 |
| 2019 | -0.1°C | -4.6°C | -9.1°C | 15.1°C | -28.4°C | 69 mm | 86% | 4 m/s | 1.8 |
| 2018 | 0.8°C | -4.2°C | -9.2°C | 16.0°C | -24.4°C | 23 mm | 80% | 4.2 m/s | 2 |
| 2017 | 3.5°C | -0.4°C | -4.4°C | 16.9°C | -17.6°C | 64 mm | 83% | 3.9 m/s | 1.4 |
| 2016 | 1.2°C | -3.2°C | -7.5°C | 16.5°C | -17.9°C | 22 mm | 86% | 4 m/s | 2.1 |
| 2015 | 0.3°C | -4.1°C | -8.6°C | 7.7°C | -22.8°C | 41 mm | 85% | 3.5 m/s | 2 |
| 2014 | -2.0°C | -7.2°C | -12.4°C | 9.6°C | -27.8°C | 49 mm | 81% | 4.8 m/s | 1.9 |
| 2013 | 2.8°C | -2.1°C | -7.1°C | 16.2°C | -15.7°C | 75 mm | 80% | 4.1 m/s | 2.1 |
| 2012 | 4.3°C | -0.2°C | -4.7°C | 15.8°C | -12.5°C | 38 mm | 80% | 4.2 m/s | 2 |
| 2011 | -1.3°C | -5.1°C | -8.9°C | 4.7°C | -20.1°C | 26 mm | 84% | 3.3 m/s | 1.5 |
| 2010 | -2.3°C | -5.8°C | -9.3°C | 7.6°C | -20.4°C | 37 mm | 91% | 3.6 m/s | 1.8 |
| 2009 | -1.5°C | -6.1°C | -10.7°C | 7.8°C | -23.4°C | 16 mm | 85% | 3.8 m/s | 2 |
| 2008 | 2.2°C | -2.8°C | -7.7°C | 19.1°C | -18.1°C | 92 mm | 81% | 4.8 m/s | 2 |
| 2007 | 2.4°C | -1.7°C | -5.8°C | 11.8°C | -14.3°C | 71 mm | 85% | 4.1 m/s | 1.8 |
| 2006 🔥 | 7.4°C | 2.9°C | -1.7°C | 15.6°C | -4.7°C | 56 mm | 85% | 4.1 m/s | 1.8 |
| 2005 🌧️ | 1.2°C | -3.3°C | -7.8°C | 16.7°C | -16.2°C | 157 mm | 89% | 3.5 m/s | 1.7 |
| 2004 | -0.8°C | -5.6°C | -10.3°C | 18.3°C | -24.8°C | 45 mm | 83% | 3.9 m/s | 1.9 |
| 2003 | -1.0°C | -5.2°C | -9.3°C | 10.3°C | -20.0°C | 19 mm | 76% | 3.8 m/s | 2 |
| 2002 | 4.8°C | 0.4°C | -4.0°C | 14.1°C | -14.3°C | 73 mm | 85% | 3.6 m/s | 2.2 |
| 2001 | 0.6°C | -3.6°C | -7.9°C | 5.0°C | -17.0°C | 59 mm | 91% | 3.2 m/s | 2 |
| 2000 | 1.6°C | -2.7°C | -7.0°C | 15.1°C | -16.0°C | 24 mm | 78% | 4 m/s | 2 |
| 1999 | 0.3°C | -4.5°C | -9.3°C | 15.7°C | -30.3°C | 87 mm | 93% | 4 m/s | 2 |
| 1998 | 3.0°C | -1.2°C | -5.4°C | 14.7°C | -17.5°C | 65 mm | 91% | 3.1 m/s | 1.6 |
| 1997 | -1.2°C | -6.2°C | -11.3°C | 20.4°C | -26.0°C | 61 mm | 85% | 4.1 m/s | 1.7 |
| 1996 | -0.4°C | -5.3°C | -10.2°C | 15.0°C | -22.5°C | 51 mm | 84% | 4.5 m/s | 1.7 |
| 1995 | 0.1°C | -3.9°C | -8.0°C | 7.5°C | -15.7°C | 87 mm | 87% | 3.5 m/s | 1.7 |
| 1994 | -3.2°C | -6.7°C | -10.3°C | 8.9°C | -26.4°C | 48 mm | 89% | 3.8 m/s | 2 |
| 1993 | 0.8°C | -3.7°C | -8.2°C | 11.2°C | -17.7°C | 103 mm | 90% | 3.7 m/s | 1.9 |
| 1992 | 2.3°C | -1.6°C | -5.5°C | 7.1°C | -19.5°C | 47 mm | 87% | 3.7 m/s | 1.6 |
| 1991 | -2.7°C | -7.5°C | -12.3°C | 2.0°C | -20.7°C | 37 mm | 93% | 3.4 m/s | 2.2 |
| 1990 | 6.9°C | 1.7°C | -3.6°C | 16.7°C | -6.8°C | 42 mm | 77% | 4.3 m/s | 2.1 |
| 1989 | 5.5°C | 0.6°C | -4.3°C | 17.6°C | -12.6°C | 30 mm | 83% | 3.8 m/s | 1.9 |
| 1988 | -1.4°C | -6.1°C | -10.8°C | 14.0°C | -23.5°C | 57 mm | 84% | 4.4 m/s | 1.8 |
| 1987 | -0.5°C | -4.7°C | -9.0°C | 7.8°C | -26.6°C | 46 mm | 91% | 3.3 m/s | 1.8 |
| 1986 | 1.3°C | -3.6°C | -8.5°C | 13.6°C | -21.3°C | 2 mm | 85% | 4.1 m/s | 2.1 |
| 1985 | -4.9°C | -10.3°C | -15.7°C | 1.5°C | -32.5°C | 16 mm | 90% | 4.4 m/s | 2.2 |
| 1984 | -2.0°C | -6.6°C | -11.2°C | 6.4°C | -26.5°C | 16 mm | 89% | 3.6 m/s | 1.9 |
| 1983 | 1.4°C | -2.2°C | -5.8°C | 6.3°C | -12.7°C | 15 mm | 87% | 3.7 m/s | — |
| 1982 ❄️ | -5.4°C | -11.6°C | -17.8°C | 1.7°C | -35.9°C | 107 mm | 94% | 4.3 m/s | — |
| 1981 | 0.6°C | -4.3°C | -9.3°C | 11.3°C | -17.9°C | 11 mm | 77% | 3.5 m/s | — |
Actual recorded January data for each year, 1981–2025 — sourced from NASA POWER.
The average high in January is around 0.8°C with lows near -8.3°C (mean -3.8°C), based on 45 years of NASA POWER data.
January averages 53 mm of rainfall in Decatur, one of the drier months. The wettest on record was 157 mm in 2005.
The hottest January reached 20.4°C in 1997. The coldest dipped to -35.9°C in 1982.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average January temperatures have risen by about 3.9°C. Daytime highs moved from -2.1°C to 1.2°C and overnight lows from -12°C to -7.4°C over the same span.
January is one of the cooler months of the year in Decatur and one of the drier months, so plan for around 0.8°C daytime highs and -8.3°C at night.
Yes — January is the coldest month of the year in Decatur, averaging -3.8°C.
For January in Decatur, pack warm layers and a jacket for chilly mornings, with typical highs of 0.8°C and lows of -8.3°C. Bring an umbrella or light rain jacket too.
Relative humidity in January averages 85% — quite humid.
Average wind speed in January is 3.9 m/s. The windiest January on record averaged 4.8 m/s (2008).
The wettest January on record was 2005 with 157 mm. On average, January sees 53 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 Decatur 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.
