December weather in Johnston, IA
The average temperature in Johnston in December is 27.1°F (19.0°F–35.2°F). Average precipitation: 1.46 inches. Average snowfall is 8.3 inches.
December is a winter month in Johnston, and is cooler than the annual average of 50.3°F. Daily temperatures swing about 16.2°F between overnight low and afternoon high. Expect about 8 days with precipitation. Daylight averages about 8h 59m. For travel, December is cold.
Avg High
35.2°F
Avg Low
19.0°F
Precipitation
1.46 in
Snow
8.3 in
December records in Johnston
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| December 1 | 64.9°F (1998) | 5.0°F (2005) | 1.12 in (2007) |
| December 2 | 64.0°F (1995) | 9.0°F (2005) | 0.23 in (2003) |
| December 3 | 66.0°F (2012) | 3.9°F (2025) | 1.27 in (2011) |
| December 4 | 69.1°F (1998) | -6.0°F (2025) | 0.38 in (2016) |
| December 5 | 66.9°F (2001) | -5.1°F (2005) | 0.31 in (2004) |
| December 6 | 53.1°F (2001) | -7.1°F (2005) | 0.30 in (2025) |
| December 7 | 64.0°F (2024) | -11.9°F (2005) | 0.04 in (2005) |
| December 8 | 61.0°F (2024) | -5.1°F (2005) | 0.99 in (2009) |
| December 9 | 61.0°F (2020) | -7.1°F (2005) | 0.34 in (2003) |
| December 10 | 64.0°F (2020) | -8.0°F (2009) | 0.13 in (2000) |
| December 11 | 51.1°F (2001) | -2.9°F (2000) | 0.73 in (2007) |
| December 12 | 54.0°F (2021) | -15.0°F (2000) | 0.72 in (2015) |
| December 13 | 55.0°F (2006) | -7.1°F (2025) | 2.37 in (2015) |
| December 14 | 60.1°F (2021) | -9.0°F (2025) | 1.23 in (2015) |
| December 15 | 73.0°F (2021) | -5.1°F (2008) | 0.53 in (2014) |
| December 16 | 57.0°F (2006) | -2.9°F (2008) | 0.20 in (2008) |
| December 17 | 48.9°F (2018) | -7.1°F (2000) | 0.08 in (2024) |
| December 18 | 57.0°F (2018) | -16.1°F (2016) | 0.42 in (2008) |
| December 19 | 57.0°F (2018) | -6.0°F (1996) | 0.66 in (2012) |
| December 20 | 52.0°F (2015) | -8.0°F (1996) | 0.80 in (2006) |
| December 21 | 52.0°F (2019) | -9.0°F (1999) | 0.25 in (2006) |
| December 22 | 57.0°F (2019) | -13.0°F (2000) | 0.36 in (2013) |
| December 23 | 53.1°F (2020) | -9.9°F (2022) | 1.03 in (2015) |
| December 24 | 57.0°F (2021) | -16.1°F (2000) | 0.61 in (2023) |
| December 25 | 61.0°F (2019) | -15.0°F (2000) | 0.76 in (2023) |
| December 26 | 57.9°F (2008) | -8.0°F (2017) | 0.49 in (2018) |
| December 27 | 57.0°F (2008) | -11.0°F (2017) | 0.61 in (2018) |
| December 28 | 59.0°F (2002) | 1.0°F (2009) | 0.75 in (2019) |
| December 29 | 59.0°F (1999) | -5.1°F (2009) | 0.56 in (2020) |
| December 30 | 62.1°F (2004) | -6.0°F (1998) | 0.37 in (2024) |
| December 31 | 55.0°F (2011) | -18.9°F (2017) | 0.94 in (2006) |