Deerfield weather in January

In January, Deerfield sees average daytime highs of 30°F and overnight lows near 21°F, with 2.9 in of precipitation across 9.8 wet days and about 9.3 hours of daylight. It is the 12th-warmest and 11th-wettest month of the year here.

Highs ease over the month, from about 33°F in the first days to 29°F by the end. The sky is clear or mostly clear about 17% 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 Deerfield's 12th-clearest and 3rd-windiest month. For the whole year in context, see Deerfield's year-round climate.

Daytime high
30°
12th warmest
Overnight low
21°
2nd coldest
Precipitation
2.9 in
9.8 wet days
Daylight
9 h 12 min
7:23 AM – 4:38 PM
Cloud cover
76%
12th clearest
Wind
14 mph
3rd windiest
Solar energy
1.83 kWh/m²
Travel score
0.0
out of 10

Deerfield is village in Illinois, United States.

Founded
1903

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

Temperature in January

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 33°F in the first days to 29°F by the end.

A typical January day in Deerfield reaches about 30°F in the afternoon and slips back to 21°F overnight — a 9°F spread between the day's warmth and the night's chill. On most days the high lands between 18°F and 40°F. Set against its neighbours, January runs about 6°F cooler than December and on par with February.

20°40°151015202531
Avg high (°F)Avg low (°F)
13325
23324
33324
43224
53224
63224
73223
83123
93123
103122
113122
123122
133122
143021
153021
163021
173021
183020
193020
202920
212920
222920
232920
242920
252920
262920
272920
282920
292920
302920
312920

How January really feels in Deerfield

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.

Deerfield 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
Jan30° / 21°2.99.879.30.0
Feb31° / 21°2.47.75.110.30.0
Mar37° / 29°3.09.83.211.60.0
Apr46° / 39°4.8121.413.11.3
May58° / 50°4.111.7014.44.1
Jun71° / 64°3.510.50156.5
Jul78° / 70°3.110.5014.86.8
Aug77° / 70°3.810.7013.77.0
Sep71° / 63°3.39.5012.36.8
Oct58° / 51°4.010.50.110.84.4
Nov46° / 39°3.4101.39.61.2
Dec36° / 28°3.1104.990.0

Cloud cover in January

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 17% of the time in January, the cloudiest month of the year.

Beyond those clear spells, partly cloudy skies cover about 10% of January, with mostly cloudy or overcast conditions the remaining 73%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
12377
22377
32377
42377
52278
62278
72377
82377
92377
102476
112476
122476
132575
142674
152773
162872
172872
182971
193070
203070
213070
223070
233070
243169
253169
263169
273169
283169
293268
303367
313367

Chance of precipitation in January

Any precipitationSnow

Deerfield gets around 2.9 in of rain and snow over 9.8 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 31% and peaks near 34% on the wettest days, and about 7 days bring snow.

0%10%20%30%40%151015202531
Rain chance (%)Snow chance (%)
13319
23319
33320
43420
53421
63421
73422
83422
93422
103322
113322
123322
133223
143223
153223
163223
173123
183123
193023
203023
213023
222923
232923
242923
252923
262823
272823
282822
292822
302722
312721

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 14 mph in January.

Across January, daily wind ranges from about 13 mph on the calmest days to 15 mph at its breeziest. It stays fairly steady from day to day.

05101520151015202531
Wind speed (mph)Feels
115breezy
215breezy
315breezy
415breezy
515breezy
615breezy
715breezy
815breezy
915breezy
1015breezy
1115breezy
1214breezy
1314breezy
1414breezy
1514breezy
1614breezy
1714breezy
1814breezy
1914breezy
2014breezy
2114breezy
2214breezy
2314breezy
2414breezy
2514breezy
2613breezy
2713breezy
2813breezy
2913breezy
3013breezy
3113breezy

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 7:14 AM, and sunset from 4:24 PM to 4:56 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.07:254:24
29.07:264:24
39.07:264:25
49.07:264:26
59.07:264:27
69.07:264:28
79.17:264:29
89.17:254:30
99.17:254:31
109.17:254:32
119.17:254:33
129.17:254:34
139.27:244:35
149.27:244:36
159.27:244:37
169.27:234:38
179.37:234:39
189.37:234:40
199.37:224:41
209.37:224:42
219.47:214:44
229.47:204:45
239.47:204:46
249.57:194:47
259.57:184:48
269.57:184:50
279.67:174:51
289.67:164:52
299.67:154:53
309.77:144:55
319.77:144:56

Solar energy in January

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in January, about 1.83 kWh/m².

For context, solar energy here swings from a low near 1.48 kWh/m² to a high of 6.5 kWh/m² in June across the year — January's 1.83 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
11.5Dim
21.5Dim
31.5Dim
41.5Dim
51.6Dim
61.6Dim
71.6Dim
81.6Dim
91.6Dim
101.6Dim
111.7Dim
121.7Dim
131.7Dim
141.8Dim
151.8Dim
161.8Dim
171.9Dim
181.9Dim
191.9Dim
201.9Dim
212.0Dim
222.0Moderate
232.1Moderate
242.1Moderate
252.1Moderate
262.2Moderate
272.2Moderate
282.3Moderate
292.3Moderate
302.3Moderate
312.4Moderate
Planning a trip in January

Is January a good time to visit Deerfield?

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

0.0
Sightseeing
9th-best month of the year
0.0
Beach & pool
7th-best month of the year

January is a weaker month for outdoor sightseeing in Deerfield.

What to pack for Deerfield in January

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

In January, Deerfield sees daytime highs around 30°F and nights near 21°F. Pack a warm layer and a heavy coat. Worth having: rain gear and a windbreaker. About 10 days see rain.

a warm layera heavy coatrain geara windbreaker

Sea temperature near Deerfield 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 12 mi away) is warmest in August at about 72°F and coldest in February near 36°F.

It's comfortable for a long swim from Jul 14 to Sep 14 — 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
May44Bracing
Jun56Bracing
Jul69Refreshing
Aug72Refreshing
Sep68Refreshing
Oct58Bracing
Nov48Bracing
Dec42Bracing

UV index in Deerfield 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 Deerfield peaks around June 23 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 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 23UV 9Dec 22UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar4Moderate
Apr6High
May7Very high
Jun9Very high
Jul9Very high
Aug8Very high
Sep6High
Oct3Moderate
Nov2Moderate
Dec2Low

Air quality in Deerfield 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 Deerfield 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 Deerfield?

Deerfield sits at 42.2°N, 87.8°W, 686 ft above sea level, in United States. The nearest listed city is Highland Park, 2.5 mi away.

Topography around Deerfield

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

Within 2 miles, the terrain around Deerfield has only modest variations in elevation — a maximum elevation change of 138 ft around an average of 676 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 269 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 892 ft.

The land around Deerfield is covered by trees (51%) and artificial surfaces (31%) within 2 miles, trees (36%), water (28%) and artificial surfaces (23%) within 10 miles, and water (40%) within 50 miles.

2 miles
138 ft
10 miles
269 ft
50 miles
892 ft
treesgrasslandcroplandartificial surfaceswater
January weather nearby: Highland Park 2.5 mi · Northbrook 3.1 mi · Wheeling 5.0 mi · Lake Forest 6.2 mi · Buffalo Grove 6.2 mi · Prospect Heights 6.8 mi · Glenview 7.5 mi · Vernon Hills 7.5 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 Deerfield (42.1711°, -87.8445°, elevation 686 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).