December weather in Royal, IL
The average temperature in Royal in December is 31.6°F (23.9°F–39.3°F). Average precipitation: 2.35 inches. Average snowfall is 5.5 inches.
December is a winter month in Royal, and is cooler than the annual average of 52.2°F. Daily temperatures swing about 15.4°F between overnight low and afternoon high. Expect about 11 days with precipitation. Daylight averages about 9h 9m. For travel, December is cold.
Avg High
39.3°F
Avg Low
23.9°F
Precipitation
2.35 in
Snow
5.5 in
December records in Royal
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| December 1 | 64.0°F (2014) | 10.9°F (2024) | 1.62 in (2006) |
| December 2 | 64.0°F (2012) | 10.0°F (2024) | 0.43 in (2018) |
| December 3 | 66.9°F (2012) | 10.0°F (2024) | 0.43 in (2007) |
| December 4 | 72.0°F (2012) | 10.9°F (2024) | 0.55 in (2010) |
| December 5 | 64.0°F (2017) | -0.9°F (2025) | 0.45 in (2016) |
| December 6 | 55.9°F (2021) | -0.9°F (2025) | 0.64 in (2014) |
| December 7 | 50.0°F (2012) | 7.0°F (2024) | 1.01 in (2004) |
| December 8 | 55.9°F (2023) | 9.0°F (2013) | 0.37 in (2012) |
| December 9 | 57.9°F (2023) | 10.9°F (2025) | 0.49 in (2009) |
| December 10 | 57.0°F (2023) | 3.0°F (2013) | 0.43 in (2007) |
| December 11 | 62.1°F (2021) | 3.0°F (2013) | 0.71 in (2021) |
| December 12 | 60.1°F (2020) | -0.9°F (2013) | 0.88 in (2010) |
| December 13 | 66.9°F (2015) | -0.9°F (2013) | 0.85 in (2009) |
| December 14 | 62.1°F (2015) | -8.0°F (2025) | 0.49 in (2015) |
| December 15 | 57.9°F (2011) | -13.0°F (2025) | 1.15 in (2022) |
| December 16 | 63.0°F (2021) | -5.1°F (2025) | 0.34 in (2007) |
| December 17 | 57.0°F (2015) | 16.0°F (2013) | 1.08 in (2023) |
| December 18 | 50.0°F (2017) | 10.0°F (2013) | 0.30 in (2021) |
| December 19 | 51.1°F (2025) | -2.0°F (2016) | 1.28 in (2008) |
| December 20 | 53.1°F (2011) | -2.0°F (2016) | 0.89 in (2012) |
| December 21 | 59.0°F (2013) | 12.9°F (2016) | 0.78 in (2015) |
| December 22 | 55.9°F (2015) | 15.1°F (2024) | 1.31 in (2013) |
| December 23 | 55.9°F (2015) | -9.9°F (2022) | 0.94 in (2003) |
| December 24 | 62.1°F (2015) | -9.0°F (2022) | 0.83 in (2008) |
| December 25 | 61.0°F (2023) | -0.9°F (2022) | 0.70 in (2009) |
| December 26 | 62.1°F (2019) | 1.9°F (2022) | 0.21 in (2009) |
| December 27 | 64.0°F (2019) | -6.0°F (2017) | 2.63 in (2015) |
| December 28 | 60.1°F (2025) | -7.1°F (2017) | 1.56 in (2008) |
| December 29 | 68.0°F (2025) | 3.9°F (2017) | 1.71 in (2015) |
| December 30 | 57.0°F (2019) | 9.0°F (2025) | 1.06 in (2024) |
| December 31 | 54.0°F (2022) | -0.9°F (2017) | 0.62 in (2018) |