Romeoville weather in January

In January, Romeoville sees average daytime highs of 31°F and overnight lows near 18°F, with 2.1 in of precipitation across 8.3 wet days and about 9.3 hours of daylight. It is the 12th-warmest and 11th-wettest month of the year here.

Day-to-day highs hold fairly steady near 31°F through the month. The sky is clear or mostly clear about 21% of the time in January, and the air most often feels dry.

Daylight stretches from about 9 hours at the start of January to 9 h 42 min by month's end. Set against the rest of the year, January is Romeoville's 12th-clearest and 3rd-windiest month. For the whole year in context, see Romeoville's year-round climate.

Daytime high
31°
12th warmest
Overnight low
18°
1st coldest
Precipitation
2.1 in
8.3 wet days
Daylight
9 h 18 min
7:23 AM – 4:40 PM
Cloud cover
71%
12th clearest
Wind
9 mph
3rd windiest
Solar energy
1.92 kWh/m²
Travel score
0.0
out of 10

Romeoville is village in Will County, Illinois, United States.

Density
818/km²
people per km²
Founded
1895

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in January

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 31°F through the month.

A typical January day in Romeoville reaches about 31°F in the afternoon and slips back to 18°F overnight — a 13°F spread between the day's warmth and the night's chill. On most days the high lands between 17°F and 45°F. Set against its neighbours, January runs about 5°F cooler than December and about 4°F cooler than February.

20°40°151015202531
Avg high (°F)Avg low (°F)
13321
23320
33320
43320
53320
63219
73219
83219
93219
103119
113118
123118
133118
143118
153117
163117
173117
183017
193017
203017
213017
223017
233117
243117
253117
263117
273117
283117
293118
303118
313118

How January really feels in Romeoville

Once humidity and wind are folded in, January averages 0 days that feel above 90°F and 31 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
31
31 feel bitter (≤ 14°F)

The story in January is cold — wind chill drags the overnight "feels like" below the raw low.

Romeoville weather by month

How January compares with the rest of the year at a glance. January is the 12th-warmest and 11th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan31° / 18°2.18.35.99.30.0
Feb35° / 21°2.07.14.610.30.0
Mar47° / 30°2.710.12.911.71.4
Apr59° / 40°4.412.2113.14.2
May69° / 51°4.412.7014.35.9
Jun79° / 61°4.212.20156.2
Jul83° / 66°3.711.4014.75.8
Aug81° / 64°3.710.9013.76.5
Sep74° / 56°2.98.3012.37.1
Oct62° / 44°3.19.10.110.95.3
Nov48° / 33°2.58.31.39.71.7
Dec36° / 24°2.284.290.0

Cloud cover in January

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 21% of the time in January, the cloudiest month of the year.

Beyond those clear spells, partly cloudy skies cover about 11% of January, with mostly cloudy or overcast conditions the remaining 68%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13169
23169
33169
43169
53070
63070
73070
82971
93070
103169
113169
123169
133169
143268
153268
163268
173268
183367
193367
203268
213268
223268
233268
243367
253367
263268
273169
283169
293169
303169
313169

Chance of precipitation in January

Any precipitationSnow

Romeoville gets around 2.1 in of rain and snow over 8.3 wet days in January. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 26% and peaks near 28% on the wettest days, and about 6 days bring snow.

0%10%20%30%40%151015202531
Rain chance (%)Snow chance (%)
12616
22616
32717
42717
52818
62818
72818
82819
92819
102819
112819
122819
132819
142819
152819
162719
172719
182719
192720
202620
212620
222620
232520
242519
252519
262419
272419
282419
292319
302319
312318

Humidity in January

DryComfortableHumidMuggyOppressiveMiserable

Most of January feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, January lands in the dry band about 100% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)
1100
2100
3100
4100
5100
6100
7100
8100
9100
10100
11100
12100
13100
14100
15100
16100
17100
18100
19100
20100
21100
22100
23100
24100
25100
26100
27100
28100
29100
30100
31100

Wind in January

Winds average 9 mph in January.

Across January, daily wind ranges from about 9 mph on the calmest days to 9 mph at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (mph)Feels
19light breeze
29light breeze
39light breeze
49light breeze
59light breeze
69light breeze
79light breeze
89light breeze
99light breeze
109light breeze
119light breeze
129light breeze
139light breeze
149light breeze
159light breeze
169light breeze
179light breeze
189light breeze
199light breeze
209light breeze
219light breeze
229light breeze
239light breeze
249light breeze
259light breeze
269light breeze
279light breeze
289light breeze
299light breeze
309light breeze
319light breeze

Sunrise & sunset in January

DaylightNight

Daylight runs from about 9 hours at the start of January to 9 h 42 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 42 minutes over January. Sunrise moves from 7:25 AM to 7:13 AM, and sunset from 4:26 PM to 4:58 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.07:254:26
29.07:254:27
39.17:254:28
49.17:254:29
59.17:254:30
69.17:254:31
79.17:254:31
89.17:254:32
99.17:254:33
109.27:244:34
119.27:244:35
129.27:244:36
139.27:244:37
149.27:244:38
159.37:234:39
169.37:234:40
179.37:224:42
189.37:224:43
199.47:214:44
209.47:214:45
219.47:204:46
229.57:204:47
239.57:194:48
249.57:194:50
259.57:184:51
269.67:174:52
279.67:174:53
289.67:164:54
299.77:154:56
309.77:144:57
319.77:134:58

Solar energy in January

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in January, about 1.92 kWh/m².

For context, solar energy here swings from a low near 1.63 kWh/m² to a high of 6.42 kWh/m² in June across the year — January's 1.92 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
11.6Dim
21.6Dim
31.7Dim
41.7Dim
51.7Dim
61.7Dim
71.7Dim
81.7Dim
91.8Dim
101.8Dim
111.8Dim
121.8Dim
131.9Dim
141.9Dim
151.9Dim
161.9Dim
171.9Dim
182.0Dim
192.0Moderate
202.0Moderate
212.1Moderate
222.1Moderate
232.1Moderate
242.1Moderate
252.2Moderate
262.2Moderate
272.2Moderate
282.3Moderate
292.3Moderate
302.3Moderate
312.4Moderate
Planning a trip in January

Is January a good time to visit Romeoville?

Our two travel scores rate January for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

0.0
Sightseeing
10th-best month of the year
0.0
Beach & pool
9th-best month of the year

January is a weaker month for outdoor sightseeing in Romeoville.

What to pack for Romeoville in January

From January's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In January, Romeoville sees daytime highs around 31°F and nights near 18°F. Pack a warm layer and a heavy coat. Worth having: rain gear. About 8 days see rain.

a warm layera heavy coatrain gear

Sea temperature near Romeoville in January

The nearest coast averages about 38°F in January — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 29 mi away) is warmest in August at about 73°F and coldest in February near 36°F.

It's comfortable for a long swim from Jul 13 to Sep 15 — about 2.1 months when the water holds above 68°F.

30°40°50°60°70°80°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°F)Comfort
Jan38Bracing
Feb36Bracing
Mar36Bracing
Apr39Bracing
May45Bracing
Jun57Bracing
Jul70Refreshing
Aug73Refreshing
Sep68Refreshing
Oct58Bracing
Nov49Bracing
Dec42Bracing

UV index in Romeoville in January

LowModerateHighVery highExtreme

Clear-sky midday UV in January peaks around 2. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Romeoville peaks around June 22 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJun 22UV 9Dec 21UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May7Very high
Jun9Very high
Jul9Very high
Aug8Very high
Sep6High
Oct3Moderate
Nov2Moderate
Dec2Low

Air quality in Romeoville in January

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where January falls, not just the annual average.

Air quality in Romeoville is worst in July — around 21 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (October, 10 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodJul 921 µg/m³Oct 2410 µg/m³
PM2.5 (µg/m³)Level
Jan12Moderate
Feb15Moderate
Mar18Moderate
Apr19Moderate
May20Moderate
Jun21Moderate
Jul21Moderate
Aug18Moderate
Sep15Moderate
Oct10Good
Nov10Good
Dec11Good
Location & terrain

Where is Romeoville?

Romeoville sits at 41.6°N, 88.1°W, 620 ft above sea level, in United States. The nearest listed city is Bolingbrook, 3.7 mi away.

Topography around Romeoville

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Romeoville.

Within 2 miles, the terrain around Romeoville has only modest variations in elevation — a maximum elevation change of 167 ft around an average of 636 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 427 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 751 ft.

The land around Romeoville is covered by artificial surfaces (46%) and grassland (25%) within 2 miles, trees (34%), artificial surfaces (26%) and grassland (25%) within 10 miles, and cropland (46%) within 50 miles.

2 miles
167 ft
10 miles
427 ft
50 miles
751 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
January weather nearby: Bolingbrook 3.7 mi · Lockport 4.3 mi · Lemont 5.0 mi · Plainfield 6.2 mi · Crest Hill 6.2 mi · Woodridge 7.5 mi · Goodings Grove 8.1 mi · Joliet 8.7 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Romeoville (41.6475°, -88.0895°, elevation 620 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).