Climate almanac
Decatur
Illinois, United States · 39.84°, -88.95°
What is the weather like in Decatur in January?
In January, Decatur is typically 37°F (3°C) during the day and 23°F (-5°C) at night. The month brings about 2.8 in (72 mm) of precipitation in total. Snowfall averages about 4.8 in (123 mm) over the month.
- Average high37°F (3°C)
- Average low23°F (-5°C)
- Precipitation2.8 in (72 mm)
- Clear or mostly clear days7
- Snowfall4.8 in (123 mm)
- Based on2016-2025 daily ERA5 reanalysis data (10-year normals)