Rock County Weather in January
Average highs run from 30°F on January 1 to 29°F on January 31, and lows from 14°F to 11°F. Normal precipitation for the month is 1.63 in over about 10 wet days.
January day by day
The normal high and low for each date, and the record, in °F.
- Normal low
- Normal high
- Record high
- Record low
January at a glance
- Average high
- 28°F
- Average low
- 12°F
- Precipitation
- 1.63 in
- Snowfall
- 10.8 in
- Record high
- 60°FJan 7, 2008
- Record low
- -30°FJan 31, 2019
- Chance of a freeze
- 100%
- Daylight
- 9 h 07 min to 9 h 58 min
- Cloud cover
- 66%
- Humidity
- 89%
- Dew point
- 16°F
- Wind
- 12.3 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 |
|---|---|---|---|---|---|---|
| Jan 1 | 30°F | 14°F | 51°F 2007 | -14°F 2018 | 32% | 18% |
| Jan 2 | 29°F | 14°F | 48°F 2005 | -15°F 1991 | 32% | 18% |
| Jan 3 | 29°F | 13°F | 56°F 2000 | -15°F 2014 | 32% | 19% |
| Jan 4 | 29°F | 13°F | 54°F 1998 | -15°F 1988 | 32% | 19% |
| Jan 5 | 29°F | 13°F | 59°F 1997 | -23°F 1999 | 32% | 19% |
| Jan 6 | 29°F | 13°F | 56°F 2008 | -23°F 1999 | 32% | 19% |
| Jan 7 | 29°F | 13°F | 60°F 2008 | -23°F 1999 | 32% | 20% |
| Jan 8 | 29°F | 12°F | 50°F 2019 | -23°F 1999 | 32% | 20% |
| Jan 9 | 28°F | 12°F | 58°F 2026 | -19°F 1988 | 33% | 20% |
| Jan 10 | 28°F | 12°F | 54°F 2002 | -18°F 1988 | 33% | 20% |
| Jan 11 | 28°F | 12°F | 52°F 2012 | -9°F 1999 | 33% | 20% |
| Jan 12 | 28°F | 12°F | 54°F 2012 | -9°F 1997 | 33% | 21% |
| Jan 13 | 28°F | 12°F | 54°F 2006 | -12°F 2016 | 33% | 21% |
| Jan 14 | 28°F | 11°F | 53°F 2026 | -15°F 1994 | 33% | 21% |
| Jan 15 | 28°F | 11°F | 52°F 1990 | -22°F 1994 | 33% | 21% |
| Jan 16 | 28°F | 11°F | 52°F 1990 | -24°F 2009 | 33% | 21% |
| Jan 17 | 28°F | 11°F | 51°F 1990 | -24°F 2009 | 33% | 21% |
| Jan 18 | 28°F | 11°F | 55°F 1996 | -26°F 1994 | 33% | 21% |
| Jan 19 | 28°F | 11°F | 57°F 1996 | -28°F 1994 | 33% | 22% |
| Jan 20 | 28°F | 11°F | 51°F 2006 | -26°F 1994 | 33% | 22% |
| Jan 21 | 28°F | 11°F | 46°F 2018 | -26°F 1994 | 33% | 22% |
| Jan 22 | 28°F | 11°F | 53°F 2017 | -13°F 2025 | 33% | 22% |
| Jan 23 | 28°F | 11°F | 50°F 2002 | -16°F 2026 | 33% | 22% |
| Jan 24 | 28°F | 11°F | 45°F 2002 | -16°F 2026 | 32% | 22% |
| Jan 25 | 28°F | 11°F | 41°F 1993 | -14°F 1991 | 32% | 22% |
| Jan 26 | 28°F | 11°F | 50°F 2002 | -19°F 2019 | 32% | 22% |
| Jan 27 | 28°F | 11°F | 52°F 2002 | -20°F 2019 | 32% | 22% |
| Jan 28 | 28°F | 11°F | 58°F 2002 | -15°F 2014 | 32% | 21% |
| Jan 29 | 28°F | 11°F | 54°F 1988 | -15°F 2014 | 32% | 21% |
| Jan 30 | 29°F | 11°F | 58°F 2013 | -26°F 2019 | 32% | 21% |
| Jan 31 | 29°F | 11°F | 59°F 1989 | -30°F 2019 | 32% | 21% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (CST).
- January 1
- sunrise 7:27 AM, sunset 4:34 PM
- January 31
- sunrise 7:11 AM, sunset 5:09 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00470045 (Afton - Janesville Wwtp), public domain. Records: NOAA GHCN-Daily, station USC00470045, 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.