Johnson County Weather in December
Average highs run from 42°F on December 1 to 32°F on December 31, and lows from 25°F to 16°F. Normal precipitation for the month is 1.45 in over about 8 wet days.
December day by day
The normal high and low for each date, and the record, in °F.
- Normal low
- Normal high
- Record high
- Record low
December at a glance
- Average high
- 36°F
- Average low
- 20°F
- Precipitation
- 1.45 in
- Snowfall
- 7.2 in
- Record high
- 75°FDec 15, 2021
- Record low
- -19°FDec 15, 1951
- Chance of a freeze
- 100%
- Daylight
- 9 h 23 min to 9 h 13 min
- Cloud cover
- 66%
- Humidity
- 85%
- Dew point
- 22°F
- Wind
- 10.7 mph
Every day of the month
A wet day has at least 0.01 inch of precipitation; snow means at least 0.1 inch of snowfall.
| Date | Normal high | Normal low | Record high | Record low | Chance wet | Chance of snow |
|---|---|---|---|---|---|---|
| Dec 1 | 42°F | 25°F | 61°F 1998 | 5°F 2005 | 27% | 8% |
| Dec 2 | 42°F | 24°F | 62°F 1951 | 4°F 2005 | 27% | 8% |
| Dec 3 | 41°F | 24°F | 68°F 2012 | 8°F 1996 | 27% | 8% |
| Dec 4 | 41°F | 24°F | 71°F 1998 | -5°F 2025 | 27% | 8% |
| Dec 5 | 40°F | 23°F | 68°F 2001 | -5°F 2005 | 27% | 9% |
| Dec 6 | 40°F | 23°F | 64°F 1951 | -5°F 2005 | 27% | 9% |
| Dec 7 | 39°F | 23°F | 60°F 2024 | -13°F 2005 | 27% | 9% |
| Dec 8 | 39°F | 22°F | 61°F 2024 | -2°F 1995 | 27% | 10% |
| Dec 9 | 39°F | 22°F | 56°F 2020 | -11°F 2013 | 27% | 10% |
| Dec 10 | 38°F | 22°F | 60°F 2020 | -9°F 2013 | 27% | 10% |
| Dec 11 | 38°F | 21°F | 67°F 1949 | -7°F 2009 | 27% | 10% |
| Dec 12 | 37°F | 21°F | 56°F 2015 | -11°F 2000 | 27% | 11% |
| Dec 13 | 37°F | 21°F | 63°F 2015 | -5°F 2000 | 27% | 11% |
| Dec 14 | 37°F | 21°F | 60°F 2015 | -8°F 2025 | 27% | 11% |
| Dec 15 | 36°F | 20°F | 75°F 2021 | -19°F 1951 | 27% | 11% |
| Dec 16 | 36°F | 20°F | 58°F 2006 | -17°F 1951 | 27% | 11% |
| Dec 17 | 36°F | 20°F | 49°F 1949 | -10°F 1950 | 27% | 12% |
| Dec 18 | 35°F | 19°F | 57°F 2002 | -12°F 1950 | 26% | 12% |
| Dec 19 | 35°F | 19°F | 58°F 2002 | -9°F 2000 | 26% | 12% |
| Dec 20 | 35°F | 19°F | 51°F 2015 | -8°F 1950 | 26% | 12% |
| Dec 21 | 34°F | 19°F | 51°F 2019 | -8°F 1999 | 26% | 12% |
| Dec 22 | 34°F | 18°F | 55°F 2019 | -13°F 1951 | 26% | 12% |
| Dec 23 | 34°F | 18°F | 59°F 2015 | -9°F 1951 | 26% | 13% |
| Dec 24 | 34°F | 18°F | 58°F 2019 | -16°F 2013 | 26% | 13% |
| Dec 25 | 33°F | 18°F | 62°F 2019 | -16°F 2000 | 25% | 13% |
| Dec 26 | 33°F | 17°F | 50°F 2008 | -8°F 1950 | 25% | 13% |
| Dec 27 | 33°F | 17°F | 52°F 2018 | -16°F 1950 | 25% | 13% |
| Dec 28 | 33°F | 17°F | 56°F 2019 | 3°F 2000 | 25% | 13% |
| Dec 29 | 32°F | 17°F | 64°F 2022 | -1°F 2013 | 25% | 13% |
| Dec 30 | 32°F | 17°F | 62°F 2004 | -7°F 1998 | 25% | 13% |
| Dec 31 | 32°F | 16°F | 54°F 2004 | -13°F 2017 | 24% | 13% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (CST).
- December 1
- sunrise 7:14 AM, sunset 4:37 PM
- December 31
- sunrise 7:33 AM, sunset 4:46 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USW00014937 (Iowa City Muni AP), public domain. Records: NOAA GHCN-Daily, station USW00014937, every year on file, quality-flagged values removed. Cloud, humidity, wind and sunshine: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.