Marion weather in December

In December, Marion sees average daytime highs of 46°F and overnight lows near 31°F, with 3.3 in of precipitation across 8.9 wet days and about 9.4 hours of daylight. It is the 11th-warmest and 9th-wettest month of the year here.

Highs ease over the month, from about 49°F in the first days to 43°F by the end. The sky is clear or mostly clear about 28% of the time in December, and the air most often feels dry.

Daylight stretches from about 9 h 36 min at the start of December to 9 h 24 min by month's end. Set against the rest of the year, December is Marion's 11th-clearest and 6th-windiest month. For the whole year in context, see Marion's year-round climate.

Daytime high
46°
11th warmest
Overnight low
31°
3rd coldest
Precipitation
3.3 in
8.9 wet days
Daylight
9 h 24 min
7:10 AM – 4:34 PM
Cloud cover
64%
11th clearest
Wind
8 mph
6th windiest
Solar energy
1.93 kWh/m²
Travel score
1.2
out of 10

Marion is city in and the county seat of Williamson County, Illinois, United States.

Density
412/km²
people per km²
Founded
1839

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 49°F in the first days to 43°F by the end.

A typical December day in Marion reaches about 46°F in the afternoon and slips back to 31°F overnight — a 14°F spread between the day's warmth and the night's chill. On most days the high lands between 31°F and 60°F. Set against its neighbours, December runs about 10°F cooler than November and about 4°F warmer than January.

20°40°60°151015202531
Avg high (°F)Avg low (°F)
15035
24935
34934
44834
54834
64833
74733
84733
94733
104632
114632
124632
134632
144631
154531
164531
174531
184531
194531
204531
214430
224430
234430
244430
254430
264430
274430
284329
294329
304329
314329

How December really feels in Marion

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
wind chill below the day's low

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

Marion weather by month

How December compares with the rest of the year at a glance. December is the 11th-warmest and 9th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan42° / 28°3.492.39.70.3
Feb47° / 31°3.18.12.310.51.5
Mar57° / 39°4.211.40.911.74.0
Apr68° / 49°5.011.4012.96.0
May76° / 60°4.612.60146.3
Jun85° / 68°3.610.6014.65.2
Jul88° / 72°3.510.2014.34.5
Aug87° / 69°2.88.1013.55.1
Sep81° / 61°2.97.5012.36.9
Oct69° / 50°3.57.60116.9
Nov56° / 39°3.88.70.5103.9
Dec46° / 31°3.38.91.89.41.2

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 28% 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 60%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14555
24456
34456
44258
54258
64258
74159
84159
94159
104060
113961
123961
133961
143961
153961
163961
173862
183862
193862
203961
213961
223961
233961
243961
253961
263961
273961
283961
293961
303961
313961

Chance of precipitation in December

Any precipitationSnow

Marion gets around 3.3 in of rain and snow over 8.9 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 29% and peaks near 30% on the wettest days, and about 2 days bring snow.

0%10%20%30%40%151015202531
Rain chance (%)Snow chance (%)
1304
2304
3304
4304
5305
6305
7305
8306
9306
10306
11306
12306
13306
14306
15306
16306
17306
18306
19306
20296
21296
22286
23286
24286
25286
26286
27286
28276
29276
30276
31276

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 98% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)
19820
29820
39820
49721
59721
69721
79721
89721
99721
109811
119811
129910
139910
149910
159910
169910
179910
189910
199910
209910
219910
229910
239910
249910
259820
269820
279820
289820
299730
309730
319730

Wind in December

Winds average 8 mph in December.

Across December, daily wind ranges from about 8 mph on the calmest days to 8 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
18light breeze
28light breeze
38light breeze
48light breeze
58light 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
208light breeze
218light breeze
228light breeze
238light breeze
248light breeze
258light breeze
268light breeze
278light breeze
288light breeze
298light breeze
308light breeze
318light breeze

Sunrise & sunset in December

DaylightNight

Daylight runs from about 9 h 36 min at the start of December to 9 h 24 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 6:58 AM to 7:16 AM, and sunset from 4:33 PM to 4:42 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.66:584:33
29.66:594:33
39.57:004:33
49.57:014:33
59.57:024:33
69.57:024:32
79.57:034:32
89.57:044:33
99.57:054:33
109.57:064:33
119.47:064:33
129.47:074:33
139.47:084:33
149.47:094:33
159.47:094:34
169.47:104:34
179.47:104:34
189.47:114:35
199.47:124:35
209.47:124:35
219.47:134:36
229.47:134:36
239.47:144:37
249.47:144:37
259.47:144:38
269.47:154:38
279.47:154:39
289.47:154:40
299.47:164:40
309.47:164:41
319.47:164:42

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 1.93 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 1.93 kWh/m² to a high of 6.45 kWh/m² in June across the year — December's 1.93 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
12.1Moderate
22.0Moderate
32.0Moderate
42.0Moderate
52.0Moderate
62.0Dim
72.0Dim
81.9Dim
91.9Dim
101.9Dim
111.9Dim
121.9Dim
131.9Dim
141.9Dim
151.9Dim
161.9Dim
171.9Dim
181.9Dim
191.9Dim
201.9Dim
211.9Dim
221.9Dim
231.9Dim
241.9Dim
251.9Dim
261.9Dim
271.9Dim
281.9Dim
291.9Dim
301.9Dim
311.9Dim
Planning a trip in December

Is December a good time to visit Marion?

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

1.2
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 Marion.

What to pack for Marion in December

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

In December, Marion sees daytime highs around 46°F and nights near 31°F. Pack a warm layer. Worth having: a heavy coat and rain gear. About 9 days see rain.

a warm layera heavy coatrain gear

UV index in Marion 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 Marion 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 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateJun 23UV 9Dec 22UV 2
UV index (midday)Level
Jan2Moderate
Feb4Moderate
Mar5High
Apr7High
May8Very high
Jun9Very high
Jul9Very high
Aug8Very high
Sep7High
Oct4Moderate
Nov3Moderate
Dec2Moderate

Air quality in Marion 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 Marion is worst in July — around 19 µg/m³ PM2.5 (moderate), about 2.4× the cleanest month (November, 8 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1318 µg/m³Nov 128 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb11Good
Mar12Moderate
Apr11Good
May14Moderate
Jun17Moderate
Jul19Moderate
Aug14Moderate
Sep12Good
Oct8Good
Nov8Good
Dec8Good
Location & terrain

Where is Marion?

Marion sits at 37.7°N, 88.9°W, 423 ft above sea level, in United States. The nearest listed city is Carbondale, 16 mi away.

Topography around Marion

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

Within 2 miles, the terrain around Marion has only modest variations in elevation — a maximum elevation change of 148 ft around an average of 446 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 331 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,030 ft.

The land around Marion is covered by trees (32%), grassland (26%) and artificial surfaces (24%) within 2 miles, trees (51%), grassland (21%) and cropland (20%) within 10 miles, and trees (46%) and cropland (40%) within 50 miles.

2 miles
148 ft
10 miles
331 ft
50 miles
1,030 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
December weather nearby: Carbondale 16 mi · Mount Vernon 40 mi · Cape Girardeau 43 mi · Paducah 48 mi · Sikeston 69 mi · Henderson 74 mi · Evansville 77 mi · Belleville 79 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 Marion (37.7306°, -88.9331°, elevation 423 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).