Rockford weather in December: Rockford, Illinois: normal highs, lows, rain and records for December
Rockford in December has a normal high of 34°F and a normal low of 20°F, a daily mean of 27°F, falling from 40°F on the 1st to 30°F by the 31st. Measurable precipitation falls on 10 days in a normal December, 1.93 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 1°C and low of −7°C, 49 mm of precipitation and 24 cm of snow in December.
- NOAA stationRockford Greater Rockford Airport
- Station IDUSW00094822
- Location42.19°N 89.09°W
- Elevation730 ft (223 m)
- From the center5 miles
- Population147,486
- Jan 29° 15°
- Feb 33° 18°
- Mar 47° 28°
- Apr 60° 39°
- May 71° 50°
- Jun 81° 60°
- Jul 84° 64°
- Aug 82° 62°
- Sep 75° 54°
- Oct 62° 42°
- Nov 47° 31°
- Dec 34° 20°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Rockford in December?
The normal high is 34°F and the normal low 20°F, for a daily mean of 27.3°F. December is 11.5°F cooler than November and 5.5°F warmer than January. December is the 10th warmest month of the year in Rockford and the 10th wettest. Across the month the normal high falls 10°F, from 40°F on December 1 to 30°F on December 31. From one year to the next December's mean temperature typically moves about 5.3°F either way (NOAA's standard deviation), so roughly two Decembers in three average between 22°F and 33°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 32%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| December 1 | 40°F | 25°F | 32% | 16% |
| December 8 | 37°F | 22°F | 32% | 16% |
| December 15 | 34°F | 20°F | 31% | 15% |
| December 22 | 32°F | 19°F | 31% | 15% |
| December 31 | 30°F | 17°F | 32% | 15% |
Every day of December: normal high, low and chance of precipitation (warmest afternoon December 1, coldest night December 31)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| December 1 | 40°F | 25°F | 32% | 16% | 9 h 20 min |
| December 2 | 39°F | 24°F | 32% | 16% | 9 h 20 min |
| December 3 | 39°F | 24°F | 32% | 16% | 9 h 20 min |
| December 4 | 38°F | 24°F | 32% | 16% | 9 h 20 min |
| December 5 | 38°F | 23°F | 32% | 16% | 9 h 20 min |
| December 6 | 37°F | 23°F | 32% | 16% | 9 h 10 min |
| December 7 | 37°F | 23°F | 32% | 16% | 9 h 10 min |
| December 8 | 37°F | 22°F | 32% | 16% | 9 h 10 min |
| December 9 | 36°F | 22°F | 32% | 16% | 9 h 10 min |
| December 10 | 36°F | 22°F | 32% | 16% | 9 h 10 min |
| December 11 | 36°F | 21°F | 32% | 16% | 9 h 10 min |
| December 12 | 35°F | 21°F | 31% | 15% | 9 h 10 min |
| December 13 | 35°F | 21°F | 31% | 15% | 9 h 10 min |
| December 14 | 35°F | 21°F | 31% | 15% | 9 h 10 min |
| December 15 | 34°F | 20°F | 31% | 15% | 9 h 10 min |
| December 16 | 34°F | 20°F | 31% | 15% | 9 h 10 min |
| December 17 | 34°F | 20°F | 31% | 15% | 9 h 10 min |
| December 18 | 33°F | 20°F | 31% | 15% | 9 h 10 min |
| December 19 | 33°F | 19°F | 31% | 15% | 9 h 10 min |
| December 20 | 33°F | 19°F | 31% | 15% | 9 h 10 min |
| December 21 | 33°F | 19°F | 31% | 15% | 9 h 10 min |
| December 22 | 32°F | 19°F | 31% | 15% | 9 h 10 min |
| December 23 | 32°F | 18°F | 31% | 15% | 9 h 10 min |
| December 24 | 32°F | 18°F | 31% | 15% | 9 h 10 min |
| December 25 | 32°F | 18°F | 31% | 15% | 9 h 10 min |
| December 26 | 31°F | 18°F | 31% | 15% | 9 h 10 min |
| December 27 | 31°F | 17°F | 31% | 15% | 9 h 10 min |
| December 28 | 31°F | 17°F | 32% | 15% | 9 h 10 min |
| December 29 | 31°F | 17°F | 32% | 15% | 9 h 10 min |
| December 30 | 31°F | 17°F | 32% | 15% | 9 h 10 min |
| December 31 | 30°F | 17°F | 32% | 15% | 9 h 10 min |
- Normal high
- 34°FDecember average
- Normal low
- 20°FDecember average
- Precipitation
- 1.93 inmonth total
- Days with precipitation
- 100.01 inch or more
- Snowfall
- 9.4 inmonth total
- Nights at 32°F or colder
- 27
- Daylight
- 9 h 20 min to 9 h 10 minDecember 1 to December 31
- Sunshine
- 61%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00094822; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain or snow in Rockford in December?
On a given December day the chance of 0.01 inch or more is 31% on average, highest around December 31 (32%). In all, 1.93 in falls on 10 days of a normal December.
In a normal December in Rockford, 27 nights fall to freezing, 12 days stay below freezing all day and snowfall averages 9.4 inches.
Snow falls on 7 days in a normal December, and an inch or more covers the ground on 13 days.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00094822.
How humid and windy is Rockford in December?
At 3 p.m. the normal temperature is 29°F with 68% relative humidity and a dew point of 20°F; at 6 a.m. it is 21°F with 82% humidity. The wind averages 9.6 mph, most often from the west in the afternoon. A dew point under 50°F feels dry.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 21°F | 17°F | 82% | 8.5 mph | 33% |
| 9 a.m. | 23°F | 17°F | 80% | 9.5 mph | – |
| noon | 27°F | 19°F | 71% | 11.5 mph | 23% |
| 3 p.m. | 29°F | 20°F | 68% | 11.2 mph | – |
| 6 p.m. | 26°F | 19°F | 76% | 9.4 mph | 28% |
| 9 p.m. | 24°F | 18°F | 79% | 9.0 mph | – |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00094822. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for December in Rockford?
The warmest December temperature on Rockford's official record (since 1893) is 69°F, on December 3, 2012; the coldest is −24°F, on December 24, 1983. The wettest December brought 5.04 in (1971); the snowiest, 30.1 inches (2000).
The December mean against the 1991-2020 normal of 27.3°F: 2021 34.9°F (+7.6), 2022 26.3°F (−1.0), 2023 36.3°F (+9.0), 2024 29.6°F (+2.3), 2025 23.6°F (−3.7). 3 of 5 ran warmer than normal.
| December | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 34.9°F | +7.6°F | 2.42 in |
| 2022 | 26.3°F | −1.0°F | 2.56 in |
| 2023 | 36.3°F | +9.0°F | 3.13 in |
| 2024 | 29.6°F | +2.3°F | 1.13 in |
| 2025 | 23.6°F | −3.7°F | 1.78 in |
Source: records: ACIS, NWS threaded record RFDthr; recent months: ACIS, station USW00094822. Records and recent months use complete months only.
How does December in Rockford compare across Illinois?
Across the 144 places PlainClimate covers in Illinois, December normal highs run from 33°F in Galena to 48°F in Anna; Rockford's is 34°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.