Romeoville weather in January: Romeoville, Illinois: normal highs, lows, rain and records for January
Romeoville in January has a normal high of 32°F and a normal low of 16°F, a daily mean of 24°F, holding near 32°F all month. Measurable precipitation falls on 10 days in a normal January, 2.19 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 0°C and low of −9°C, 56 mm of precipitation and 27 cm of snow in January.
- NOAA stationRomeoville Weather Office
- Station IDUSC00117457
- Location41.60°N 88.08°W
- Elevation660 ft (201 m)
- From the center2 miles
- Population41,177
- Jan 32° 16°
- Feb 36° 20°
- Mar 49° 30°
- Apr 61° 40°
- May 72° 50°
- Jun 82° 60°
- Jul 85° 65°
- Aug 83° 63°
- Sep 76° 55°
- Oct 64° 44°
- Nov 49° 32°
- Dec 37° 22°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Romeoville in January?
The normal high is 32°F and the normal low 16°F, for a daily mean of 23.9°F. January is 5.5°F cooler than December and 4.1°F cooler than February. January is the 12th warmest month of the year in Romeoville and the 10th wettest, and the snowiest. Across the month the normal high falls 1°F, from 33°F on January 1 to 32°F on January 31. From one year to the next January's mean temperature typically moves about 4.9°F either way (NOAA's standard deviation), so roughly two Januarys in three average between 19°F and 29°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 35%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| January 1 | 33°F | 18°F | 35% | 18% |
| January 8 | 32°F | 17°F | 34% | 18% |
| January 15 | 31°F | 16°F | 34% | 17% |
| January 22 | 31°F | 15°F | 34% | 17% |
| January 31 | 32°F | 16°F | 34% | 17% |
Every day of January: normal high, low and chance of precipitation (warmest afternoon January 1, coldest night January 22)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| January 1 | 33°F | 18°F | 35% | 18% | 9 h 10 min |
| January 2 | 33°F | 18°F | 35% | 18% | 9 h 10 min |
| January 3 | 33°F | 18°F | 35% | 18% | 9 h 10 min |
| January 4 | 32°F | 17°F | 35% | 18% | 9 h 20 min |
| January 5 | 32°F | 17°F | 35% | 18% | 9 h 20 min |
| January 6 | 32°F | 17°F | 35% | 18% | 9 h 20 min |
| January 7 | 32°F | 17°F | 35% | 18% | 9 h 20 min |
| January 8 | 32°F | 17°F | 34% | 18% | 9 h 20 min |
| January 9 | 32°F | 17°F | 34% | 18% | 9 h 20 min |
| January 10 | 32°F | 16°F | 34% | 18% | 9 h 20 min |
| January 11 | 32°F | 16°F | 34% | 18% | 9 h 20 min |
| January 12 | 32°F | 16°F | 34% | 18% | 9 h 20 min |
| January 13 | 31°F | 16°F | 34% | 18% | 9 h 30 min |
| January 14 | 31°F | 16°F | 34% | 18% | 9 h 30 min |
| January 15 | 31°F | 16°F | 34% | 17% | 9 h 30 min |
| January 16 | 31°F | 16°F | 34% | 17% | 9 h 30 min |
| January 17 | 31°F | 16°F | 34% | 17% | 9 h 30 min |
| January 18 | 31°F | 16°F | 34% | 17% | 9 h 30 min |
| January 19 | 31°F | 15°F | 34% | 17% | 9 h 30 min |
| January 20 | 31°F | 15°F | 34% | 17% | 9 h 40 min |
| January 21 | 31°F | 15°F | 34% | 17% | 9 h 40 min |
| January 22 | 31°F | 15°F | 34% | 17% | 9 h 40 min |
| January 23 | 31°F | 15°F | 34% | 17% | 9 h 40 min |
| January 24 | 31°F | 15°F | 34% | 17% | 9 h 40 min |
| January 25 | 32°F | 15°F | 34% | 17% | 9 h 50 min |
| January 26 | 32°F | 16°F | 34% | 17% | 9 h 50 min |
| January 27 | 32°F | 16°F | 34% | 17% | 9 h 50 min |
| January 28 | 32°F | 16°F | 34% | 17% | 9 h 50 min |
| January 29 | 32°F | 16°F | 34% | 17% | 9 h 50 min |
| January 30 | 32°F | 16°F | 33% | 17% | 10 h |
| January 31 | 32°F | 16°F | 34% | 17% | 10 h |
- Normal high
- 32°FJanuary average
- Normal low
- 16°FJanuary average
- Precipitation
- 2.19 inmonth total
- Days with precipitation
- 100.01 inch or more
- Snowfall
- 10.6 inmonth total
- Nights at 32°F or colder
- 28
- Daylight
- 9 h 10 min to 10 hJanuary 1 to January 31
- Sunshine
- 61%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USC00117457; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain or snow in Romeoville in January?
On a given January day the chance of 0.01 inch or more is 34% on average, highest around January 3 (35%). In all, 2.19 in falls on 10 days of a normal January.
In a normal January in Romeoville, 28 nights fall to freezing, 16 days stay below freezing all day and snowfall averages 10.6 inches.
Snow falls on 8 days in a normal January, and an inch or more covers the ground on 15 days.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USC00117457.
What are the records for January in Romeoville?
The warmest January temperature on this station's record (since 1992) is 65°F, on January 7, 2008; the coldest is −24°F, on January 16, 2009. The wettest January brought 4.99 in (2005); the snowiest, 30.1 inches (2014).
The January mean against the 1991-2020 normal of 23.9°F: 2021 27.5°F (+3.6), 2022 18.6°F (−5.3), 2023 30.8°F (+6.9), 2024 25.0°F (+1.1), 2025 20.9°F (−3.0), 2026 20.9°F (−3.0). 3 of 6 ran warmer than normal.
| January | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 27.5°F | +3.6°F | 2.03 in |
| 2022 | 18.6°F | −5.3°F | 0.63 in |
| 2023 | 30.8°F | +6.9°F | 2.48 in |
| 2024 | 25.0°F | +1.1°F | 3.43 in |
| 2025 | 20.9°F | −3.0°F | 1.12 in |
| 2026 | 20.9°F | −3.0°F | 2.52 in |
Source: records: ACIS, station USC00117457; recent months: ACIS, station USC00117457. Records and recent months use complete months only.
How does January in Romeoville compare across Illinois?
Across the 144 places PlainClimate covers in Illinois, January normal highs run from 27°F in Galena to 45°F in Anna; Romeoville's is 32°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.