Cary weather in December

In December, Cary sees average daytime highs of 35°F and overnight lows near 22°F, with 2.1 in of precipitation across 8 wet days and about 9 hours of daylight. It is the 10th-warmest and 10th-wettest month of the year here.

Highs ease over the month, from about 38°F in the first days to 32°F by the end. The sky is clear or mostly clear about 22% of the time in December, and the air most often feels dry.

Daylight stretches from about 9 h 06 min at the start of December to 9 hours by month's end. Set against the rest of the year, December is Cary's 11th-clearest and 7th-windiest month. For the whole year in context, see Cary's year-round climate.

Daytime high
35°
10th warmest
Overnight low
22°
3rd coldest
Precipitation
2.1 in
8 wet days
Daylight
8 h 54 min
7:21 AM – 4:17 PM
Cloud cover
69%
11th clearest
Wind
8 mph
7th windiest
Solar energy
1.6 kWh/m²
Travel score
0.0
out of 10

Cary is village in Illinois, United States.

Founded
1833

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

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 38°F in the first days to 32°F by the end.

A typical December day in Cary reaches about 35°F in the afternoon and slips back to 22°F overnight — a 12°F spread between the day's warmth and the night's chill. On most days the high lands between 21°F and 48°F. Set against its neighbours, December runs about 12°F cooler than November and about 5°F warmer than January.

20°40°60°151015202531
Avg high (°F)Avg low (°F)
13927
23927
33826
43826
53825
63725
73724
83624
93624
103624
113523
123523
133523
143522
153422
163422
173422
183422
193422
203321
213321
223321
233321
243321
253321
263320
273320
283220
293220
303220
313219

How December really feels in Cary

Once humidity and wind are folded in, December 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
21 feel bitter (≤ 14°F)

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

Cary weather by month

How December compares with the rest of the year at a glance. December is the 10th-warmest and 10th-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 December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 22% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 12% of December, with mostly cloudy or overcast conditions the remaining 66%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13466
23565
33466
43466
53565
63565
73565
83565
93565
103565
113664
123664
133664
143664
153565
163565
173466
183466
193466
203565
213466
223466
233466
243466
253367
263367
273367
283367
293367
303268
313268

Chance of precipitation in December

Any precipitationSnow

Cary gets around 2.1 in of rain and snow over 8 wet days in December. 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 29% on the wettest days, and about 5 days bring snow.

0%10%20%30%40%151015202531
Rain chance (%)Snow chance (%)
12913
22913
32914
42914
52914
62815
72815
82815
92715
102715
112715
122615
132615
142614
152614
162614
172514
182514
192514
202514
212414
222414
232414
242414
252415
262415
272415
282415
292415
302516
312516

Humidity in December

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, December 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 December

Winds average 8 mph in December.

Across December, daily wind ranges from about 8 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
68light breeze
78light breeze
88light breeze
98light breeze
108light breeze
118light breeze
128light breeze
138light breeze
148light breeze
158light breeze
168light breeze
178light breeze
188light breeze
198light 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 December

DaylightNight

Daylight runs from about 9 h 06 min at the start of December to 9 hours by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 6 minutes over December. Sunrise moves from 7:08 AM to 7:27 AM, and sunset from 4:17 PM to 4:25 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.17:084:17
29.17:094:17
39.17:104:17
49.17:114:16
59.17:124:16
69.07:134:16
79.07:144:16
89.07:154:16
99.07:164:16
109.07:174:16
119.07:184:16
129.07:184:16
139.07:194:16
148.97:204:17
158.97:204:17
168.97:214:17
178.97:224:17
188.97:224:18
198.97:234:18
208.97:244:18
218.97:244:19
228.97:254:19
238.97:254:20
248.97:254:20
258.97:264:21
268.97:264:21
278.97:274:22
288.97:274:23
298.97:274:23
308.97:274:24
319.07:274:25

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 1.6 kWh/m² — the year's lowest.

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 — December's 1.6 kWh/m² sits near the bottom.

00.511.522.5151015202531
Solar energy (kWh/m²)Level
11.7Dim
21.7Dim
31.7Dim
41.7Dim
51.7Dim
61.6Dim
71.6Dim
81.6Dim
91.6Dim
101.6Dim
111.6Dim
121.6Dim
131.6Dim
141.6Dim
151.6Dim
161.6Dim
171.6Dim
181.6Dim
191.6Dim
201.6Dim
211.6Dim
221.6Dim
231.6Dim
241.6Dim
251.6Dim
261.6Dim
271.6Dim
281.6Dim
291.6Dim
301.6Dim
311.6Dim
Planning a trip in December

Is December a good time to visit Cary?

Our two travel scores rate December 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

December is a weaker month for outdoor sightseeing in Cary.

What to pack for Cary in December

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

In December, Cary sees daytime highs around 35°F and nights near 22°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 Cary in December

The nearest coast averages about 42°F in December — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 22 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 Cary in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 1. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Cary 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 Cary in December

GoodModeratePoorUnhealthyVery unhealthy

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

Air quality in Cary 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 Cary?

Cary sits at 42.2°N, 88.2°W, 823 ft above sea level, in United States. The nearest listed city is Algonquin, 4.3 mi away.

Topography around Cary

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

Within 2 miles, the terrain around Cary has only modest variations in elevation — a maximum elevation change of 213 ft around an average of 827 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 Cary is covered by trees (54%) and grassland (25%) within 2 miles, trees (43%) and grassland (28%) within 10 miles, and cropland (35%), trees (20%) and water (20%) within 50 miles.

2 miles
213 ft
10 miles
322 ft
50 miles
787 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
December weather nearby: Algonquin 4.3 mi · Crystal Lake 4.3 mi · Lake in the Hills 5.0 mi · Carpentersville 6.2 mi · Lake Zurich 7.5 mi · McHenry 8.7 mi · Huntley 9.9 mi · Round Lake 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 Cary (42.212°, -88.2381°, elevation 823 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).