Climate almanac
Decatur
Illinois, United States · 39.84°, -88.95°
What is the weather like in Decatur in December?
In December, Decatur is typically 43°F (6°C) during the day and 29°F (-2°C) at night. The month brings about 2.3 in (59 mm) of precipitation in total. Snowfall averages about 2.1 in (53 mm) over the month.
- Average high43°F (6°C)
- Average low29°F (-2°C)
- Precipitation2.3 in (59 mm)
- Clear or mostly clear days7
- Snowfall2.1 in (53 mm)
- Based on2016-2025 daily ERA5 reanalysis data (10-year normals)