Jacksonville weather in December

In December, Jacksonville sees average daytime highs of 40°F and overnight lows near 26°F, with 2.3 in of precipitation across 7.4 wet days and about 9.2 hours of daylight. It is the 11th-warmest and 11th-wettest month of the year here.

Highs ease over the month, from about 44°F in the first days to 38°F by the end. The sky is clear or mostly clear about 27% of the time in December, and the air most often feels dry.

Daylight stretches from about 9 h 24 min at the start of December to 9 h 12 min by month's end. Set against the rest of the year, December is Jacksonville's 9th-clearest and 6th-windiest month. For the whole year in context, see Jacksonville's year-round climate.

Daytime high
40°
11th warmest
Overnight low
26°
3rd coldest
Precipitation
2.3 in
7.4 wet days
Daylight
9 h 12 min
7:21 AM – 4:33 PM
Cloud cover
65%
9th clearest
Wind
8 mph
6th windiest
Solar energy
1.84 kWh/m²
Travel score
0.2
out of 10

Jacksonville is city in Morgan County, Illinois, United States.

Density
691/km²
people per km²
Founded
1825

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 44°F in the first days to 38°F by the end.

A typical December day in Jacksonville reaches about 40°F in the afternoon and slips back to 26°F overnight — a 14°F spread between the day's warmth and the night's chill. On most days the high lands between 26°F and 55°F. Set against its neighbours, December runs about 11°F cooler than November and about 5°F warmer than January.

20°40°60°151015202531
Avg high (°F)Avg low (°F)
14530
24530
34429
44429
54329
64328
74228
84228
94227
104127
114127
124127
134126
144026
154026
164026
174026
184026
193925
203925
213925
223925
233925
243824
253824
263824
273824
283824
293824
303723
313723

How December really feels in Jacksonville

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
2 feel bitter (≤ 14°F)

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

Jacksonville weather by month

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

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan36° / 21°2.37.749.50.0
Feb41° / 24°2.27.23.410.40.3
Mar52° / 34°3.110.31.611.72.8
Apr64° / 45°4.611.50.4135.4
May74° / 55°4.413.4014.26.2
Jun82° / 65°4.111.1014.85.8
Jul85° / 68°3.39.5014.55.3
Aug84° / 66°3.09013.65.7
Sep78° / 58°2.97.5012.37.3
Oct66° / 46°3.08.30.110.96.3
Nov52° / 35°3.28.20.99.82.8
Dec40° / 26°2.37.42.79.20.2

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 27% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 10% of December, with mostly cloudy or overcast conditions the remaining 63%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14159
24060
34060
43862
53961
63862
73862
83862
93763
103763
113763
123763
133664
143664
153763
163664
173664
183664
193763
203664
213763
223763
233565
243664
253664
263664
273565
283664
293763
303664
313664

Chance of precipitation in December

Any precipitationSnow

Jacksonville gets around 2.3 in of rain and snow over 7.4 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 25% and peaks near 27% on the wettest days, and about 3 days bring snow.

0%10%20%30%40%151015202531
Rain chance (%)Snow chance (%)
1277
2277
3267
4268
5258
6258
7258
8259
9259
10249
11249
12259
13259
14259
15259
16259
17259
18259
19259
20259
21249
22248
23248
24248
25238
26239
27239
28239
29239
302310
312310

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 99% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)
1982
2982
3982
4982
5982
6982
7982
8991
9991
10991
11991
12991
13991
14991
15991
161000
171000
181000
191000
201000
211000
221000
231000
241000
251000
261000
271000
281000
291000
301000
311000

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
69light 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 24 min at the start of December to 9 h 12 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 12 minutes over December. Sunrise moves from 7:09 AM to 7:27 AM, and sunset from 4:32 PM to 4:41 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.47:094:32
29.47:104:32
39.47:114:32
49.37:124:32
59.37:134:32
69.37:134:32
79.37:144:32
89.37:154:32
99.37:164:32
109.37:174:32
119.27:184:32
129.27:184:32
139.27:194:32
149.27:204:33
159.27:204:33
169.27:214:33
179.27:224:33
189.27:224:34
199.27:234:34
209.27:234:35
219.27:244:35
229.27:244:35
239.27:254:36
249.27:254:36
259.27:264:37
269.27:264:38
279.27:264:38
289.27:274:39
299.27:274:39
309.27:274:40
319.27:274:41

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 1.84 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 1.84 kWh/m² to a high of 6.46 kWh/m² in June across the year — December's 1.84 kWh/m² sits near the bottom.

00.511.522.5151015202531
Solar energy (kWh/m²)Level
11.9Dim
21.9Dim
31.9Dim
41.9Dim
51.9Dim
61.9Dim
71.9Dim
81.9Dim
91.9Dim
101.8Dim
111.8Dim
121.8Dim
131.8Dim
141.8Dim
151.8Dim
161.8Dim
171.8Dim
181.8Dim
191.8Dim
201.8Dim
211.8Dim
221.8Dim
231.8Dim
241.8Dim
251.8Dim
261.8Dim
271.8Dim
281.9Dim
291.9Dim
301.9Dim
311.9Dim
Planning a trip in December

Is December a good time to visit Jacksonville?

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

0.2
Sightseeing
11th-best month of the year
0.0
Beach & pool
10th-best month of the year

December is a weaker month for outdoor sightseeing in Jacksonville.

What to pack for Jacksonville in December

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

In December, Jacksonville sees daytime highs around 40°F and nights near 26°F. Pack a warm layer and a heavy coat. About 7 days see rain.

a warm layera heavy coat

UV index in Jacksonville in December

LowModerateHighVery highExtreme

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

Under clear skies, the midday UV index in Jacksonville peaks around June 21 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 10 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highModerateJun 21UV 9Dec 22UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May8Very high
Jun9Very high
Jul9Very high
Aug8Very high
Sep7High
Oct4Moderate
Nov3Moderate
Dec2Low

Air quality in Jacksonville 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 Jacksonville is worst in July — around 16 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (October, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodModerateGoodJul 1716 µg/m³Oct 238 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb13Moderate
Mar12Moderate
Apr11Good
May14Moderate
Jun14Moderate
Jul16Moderate
Aug14Moderate
Sep11Good
Oct8Good
Nov8Good
Dec9Good
Location & terrain

Where is Jacksonville?

Jacksonville sits at 39.7°N, 90.2°W, 610 ft above sea level, in United States. The nearest listed city is Springfield, 32 mi away.

Topography around Jacksonville

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

Within 2 miles, the terrain around Jacksonville has only modest variations in elevation — a maximum elevation change of 177 ft around an average of 604 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 243 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 604 ft.

The land around Jacksonville is covered by trees (32%), grassland (25%) and cropland (23%) within 2 miles, cropland (74%) within 10 miles, and cropland (65%) and trees (27%) within 50 miles.

2 miles
177 ft
10 miles
243 ft
50 miles
604 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
December weather nearby: Springfield 32 mi · Godfrey 54 mi · Macomb 55 mi · Upper Alton 57 mi · Alton 58 mi · Hannibal 60 mi · Old Jamestown 62 mi · Quincy 64 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 Jacksonville (39.7339°, -90.229°, elevation 610 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. 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).