December weather in DeKalb, IL
The average temperature in DeKalb in December is 26.3°F (19.1°F–33.6°F). Average precipitation: 2.04 inches. Average snowfall is 6.6 inches.
December is a winter month in DeKalb, and is cooler than the annual average of 48.5°F. Daily temperatures swing about 14.5°F between overnight low and afternoon high. Expect about 10 days with precipitation. Daylight averages about 8h 58m. For travel, December is cold.
Avg High
33.6°F
Avg Low
19.1°F
Precipitation
2.04 in
Snow
6.6 in
December records in DeKalb
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| December 1 | 63.0°F (1970) | 6.1°F (1966) | 1.68 in (2006) |
| December 2 | 63.0°F (1982) | -2.9°F (1976) | 1.88 in (1982) |
| December 3 | 66.0°F (1970) | -2.9°F (1976) | 1.26 in (1982) |
| December 4 | 69.1°F (2012) | -4.0°F (1991) | 1.20 in (1973) |
| December 5 | 64.0°F (1998) | -4.0°F (1991) | 1.28 in (1999) |
| December 6 | 64.9°F (2001) | -7.1°F (1977) | 0.51 in (1975) |
| December 7 | 57.9°F (1980) | -7.1°F (1977) | 1.25 in (1998) |
| December 8 | 52.0°F (1966) | -7.1°F (2005) | 0.78 in (1980) |
| December 9 | 57.0°F (1991) | -9.0°F (1977) | 0.85 in (2008) |
| December 10 | 53.1°F (1979) | -11.9°F (1977) | 2.03 in (2003) |
| December 11 | 55.0°F (2015) | -15.0°F (1972) | 0.76 in (1970) |
| December 12 | 53.1°F (1968) | -9.9°F (2013) | 1.03 in (1972) |
| December 13 | 60.1°F (1975) | -8.0°F (2000) | 0.60 in (1973) |
| December 14 | 60.1°F (2015) | -9.0°F (1985) | 1.53 in (1975) |
| December 15 | 59.0°F (1971) | -8.0°F (1985) | 1.06 in (1987) |
| December 16 | 64.0°F (2021) | -5.1°F (2016) | 0.85 in (1992) |
| December 17 | 53.1°F (2015) | -8.0°F (1972) | 0.25 in (1967) |
| December 18 | 51.1°F (2002) | -11.0°F (1983) | 0.35 in (1993) |
| December 19 | 55.0°F (2002) | -17.0°F (1983) | 0.86 in (2008) |
| December 20 | 53.1°F (1988) | -13.0°F (2016) | 0.81 in (1987) |
| December 21 | 57.0°F (1967) | -8.0°F (2008) | 0.73 in (2006) |
| December 22 | 51.1°F (2015) | -11.9°F (2000) | 0.60 in (1990) |
| December 23 | 57.9°F (1979) | -14.1°F (1983) | 0.59 in (1969) |
| December 24 | 57.0°F (2015) | -22.0°F (1983) | 1.02 in (1979) |
| December 25 | 60.1°F (1982) | -13.0°F (1983) | 1.27 in (2009) |
| December 26 | 55.9°F (1982) | -13.0°F (1985) | 0.54 in (2023) |
| December 27 | 59.0°F (2019) | -9.9°F (2017) | 0.52 in (1988) |
| December 28 | 64.0°F (1984) | -9.9°F (2017) | 1.03 in (1987) |
| December 29 | 63.0°F (1984) | -8.0°F (1983) | 1.52 in (2015) |
| December 30 | 57.9°F (2022) | -9.0°F (1983) | 0.86 in (2020) |
| December 31 | 57.0°F (2002) | -14.1°F (1967) | 0.83 in (1978) |