Crystal Lake weather in January

In January, Crystal Lake sees average daytime highs of 30°F and overnight lows near 17°F, with 2.0 in of precipitation across 7.9 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 30°F through the month. The sky is clear or mostly clear about 22% 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 Crystal Lake's 12th-clearest and 3rd-windiest month. For the whole year in context, see Crystal Lake's year-round climate.

Daytime high
30°
12th warmest
Overnight low
17°
1st coldest
Precipitation
2.0 in
7.9 wet days
Daylight
9 h 12 min
7:26 AM – 4:40 PM
Cloud cover
71%
12th clearest
Wind
9 mph
3rd windiest
Solar energy
1.9 kWh/m²
Travel score
0.0
out of 10

Crystal Lake is city in McHenry County, Illinois, USA.

Density
780/km²
people per km²
Founded
1914

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 30°F through the month.

A typical January day in Crystal Lake reaches about 30°F in the afternoon and slips back to 17°F overnight — a 13°F spread between the day's warmth and the night's chill. On most days the high lands between 15°F and 43°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)
13219
23119
33119
43118
53118
63118
73118
83017
93017
103017
113017
123017
132916
142916
152916
162916
172916
182915
192915
202915
212915
222915
232915
242915
252916
262916
272916
282916
292916
303016
313016

How January really feels in Crystal Lake

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.

Crystal Lake 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° / 17°2.07.969.30.0
Feb34° / 20°1.975.210.30.0
Mar45° / 29°2.59.73.311.61.1
Apr57° / 39°4.312.31.113.13.7
May68° / 50°4.312.2014.45.9
Jun78° / 61°3.811.80156.4
Jul82° / 65°3.410.4014.86.4
Aug80° / 63°3.610.6013.76.6
Sep73° / 55°3.08.8012.37.0
Oct60° / 44°3.08.70.210.85.0
Nov46° / 33°2.47.81.69.61.4
Dec35° / 22°2.184.690.0

Cloud cover in January

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 22% 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 68%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13268
23268
33268
43070
53070
63070
73070
83070
93070
103169
113169
123268
133268
143367
153466
163367
173466
183466
193466
203466
213466
223367
233367
243367
253367
263268
273268
283268
293268
303268
313268

Chance of precipitation in January

Any precipitationSnow

Crystal Lake gets around 2.0 in of rain and snow over 7.9 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 25% and peaks near 27% on the wettest days, and about 6 days bring snow.

0%10%20%30%40%151015202531
Rain chance (%)Snow chance (%)
12516
22517
32617
42617
52618
62718
72718
82719
92719
102719
112719
122719
132719
142720
152720
162720
172720
182620
192620
202520
212520
222420
232420
242420
252320
262320
272320
282320
292220
302219
312219

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 7:28 AM to 7:16 AM, and sunset from 4:25 PM to 4:58 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.07:284:25
29.07:284:26
39.07:284:27
49.07:284:28
59.07:284:29
69.07:284:30
79.07:284:30
89.17:284:31
99.17:274:32
109.17:274:33
119.17:274:34
129.17:274:35
139.27:274:36
149.27:264:37
159.27:264:39
169.27:264:40
179.37:254:41
189.37:254:42
199.37:244:43
209.37:244:44
219.47:234:45
229.47:224:46
239.47:224:48
249.57:214:49
259.57:204:50
269.57:204:51
279.67:194:53
289.67:184:54
299.67:174:55
309.77:174:56
319.77:164:58

Solar energy in January

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in January, about 1.9 kWh/m².

For context, solar energy here swings from a low near 1.6 kWh/m² to a high of 6.32 kWh/m² in June across the year — January's 1.9 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
11.6Dim
21.6Dim
31.6Dim
41.6Dim
51.7Dim
61.7Dim
71.7Dim
81.7Dim
91.7Dim
101.8Dim
111.8Dim
121.8Dim
131.8Dim
141.9Dim
151.9Dim
161.9Dim
171.9Dim
181.9Dim
192.0Dim
202.0Moderate
212.0Moderate
222.1Moderate
232.1Moderate
242.1Moderate
252.1Moderate
262.2Moderate
272.2Moderate
282.2Moderate
292.3Moderate
302.3Moderate
312.4Moderate
Planning a trip in January

Is January a good time to visit Crystal Lake?

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 Crystal Lake.

What to pack for Crystal Lake in January

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

In January, Crystal Lake sees daytime highs around 30°F and nights near 17°F. Pack a warm layer and a heavy coat. About 8 days see rain.

a warm layera heavy coat

Sea temperature near Crystal Lake 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 24 mi away) is warmest in August at about 71°F and coldest in March near 36°F.

It's comfortable for a long swim from Jul 18 to Sep 8 — about 1.7 months when the water holds above 68°F.

30°40°50°60°70°80°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°F)Comfort
Jan38Bracing
Feb36Bracing
Mar36Bracing
Apr38Bracing
May43Bracing
Jun55Bracing
Jul68Refreshing
Aug71Refreshing
Sep67Cool
Oct57Bracing
Nov47Bracing
Dec42Bracing

UV index in Crystal Lake 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 Crystal Lake peaks around June 21 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 1 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJun 21UV 9Dec 21UV 1
UV index (midday)Level
Jan2Low
Feb2Moderate
Mar4Moderate
Apr6High
May8Very high
Jun9Very high
Jul8Very high
Aug8Very high
Sep6High
Oct3Moderate
Nov2Moderate
Dec1Low

Air quality in Crystal Lake 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 Crystal Lake is worst in July — around 17 µg/m³ PM2.5 (moderate), about 1.9× the cleanest month (October, 9 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodJul 1817 µg/m³Oct 229 µg/m³
PM2.5 (µg/m³)Level
Jan12Moderate
Feb15Moderate
Mar16Moderate
Apr14Moderate
May15Moderate
Jun16Moderate
Jul17Moderate
Aug16Moderate
Sep13Moderate
Oct9Good
Nov10Good
Dec11Good
Location & terrain

Where is Crystal Lake?

Crystal Lake sits at 42.2°N, 88.3°W, 915 ft above sea level, in United States. The nearest listed city is Lake in the Hills, 4.3 mi away.

Topography around Crystal Lake

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

Within 2 miles, the terrain around Crystal Lake has only modest variations in elevation — a maximum elevation change of 171 ft around an average of 906 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 322 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 787 ft.

The land around Crystal Lake is covered by trees (47%) and artificial surfaces (27%) within 2 miles, trees (39%) and grassland (26%) within 10 miles, and cropland (38%) and trees (21%) within 50 miles.

2 miles
171 ft
10 miles
322 ft
50 miles
787 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
January weather nearby: Lake in the Hills 4.3 mi · Cary 4.3 mi · Algonquin 5.6 mi · McHenry 6.8 mi · Huntley 7.5 mi · Woodstock 8.7 mi · Carpentersville 8.7 mi · Lake Zurich 12 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 Crystal Lake (42.2411°, -88.3162°, elevation 915 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).