St. Charles weather in December

In December, St. Charles sees average daytime highs of 48°F and overnight lows near 35°F, with 3.3 in of precipitation across 8.7 wet days and about 9.4 hours of daylight. It is the 10th-warmest and 8th-wettest month of the year here.

Highs ease over the month, from about 51°F in the first days to 46°F by the end. The sky is clear or mostly clear about 36% of the time in December, and the air most often feels dry.

Daylight stretches from about 9 h 30 min at the start of December to 9 h 18 min by month's end. Set against the rest of the year, December is St. Charles's 5th-clearest and 6th-windiest month. For the whole year in context, see St. Charles's year-round climate.

Daytime high
48°
10th warmest
Overnight low
35°
3rd coldest
Precipitation
3.3 in
8.7 wet days
Daylight
9 h 18 min
7:24 AM – 4:43 PM
Cloud cover
57%
5th clearest
Wind
7 mph
6th windiest
Solar energy
2 kWh/m²
Travel score
1.8
out of 10

St. Charles is census designated place in Charles County, Maryland, United States.

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 51°F in the first days to 46°F by the end.

A typical December day in St. Charles reaches about 48°F in the afternoon and slips back to 35°F overnight — a 12°F spread between the day's warmth and the night's chill. On most days the high lands between 36°F and 60°F. Set against its neighbours, December runs about 9°F cooler than November and about 4°F warmer than January.

20°40°60°151015202531
Avg high (°F)Avg low (°F)
15239
25138
35138
45138
55038
65037
74937
84937
94937
104936
114836
124836
134836
144735
154735
164735
174735
184735
194735
204734
214734
224634
234634
244634
254634
264634
274634
284633
294633
304633
314633

How December really feels in St. Charles

Once humidity and wind are folded in, December averages 0 days that feel above 90°F and 25 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
25
wind chill below the day's low

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

St. Charles weather by month

How December compares with the rest of the year at a glance. December is the 10th-warmest and 8th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan44° / 31°3.08.72.79.60.7
Feb47° / 32°2.88.42.210.51.4
Mar55° / 39°3.910.11.511.73.5
Apr66° / 50°3.39.40136.0
May74° / 59°3.410.4014.16.7
Jun83° / 68°3.510.9014.65.7
Jul87° / 73°3.812014.44.6
Aug85° / 71°3.710.2013.55.4
Sep78° / 64°4.19.2012.36.9
Oct67° / 53°3.47.70116.6
Nov56° / 42°2.97.40.19.94.2
Dec48° / 35°3.38.71.29.41.8

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 36% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 14% of December, with mostly cloudy or overcast conditions the remaining 51%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15248
25149
35050
45050
55050
64951
74951
84852
94852
104852
114852
124753
134753
144852
154852
164852
174852
184852
194951
204951
215050
225050
235050
245050
255050
265050
275050
285050
295050
305149
315149

Chance of precipitation in December

Any precipitationSnow

St. Charles gets around 3.3 in of rain and snow over 8.7 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 28% and peaks near 30% on the wettest days, and about 1 day brings snow.

0%10%20%30%40%151015202531
Rain chance (%)Snow chance (%)
1292
2293
3293
4293
5304
6304
7304
8304
9304
10304
11304
12294
13294
14294
15294
16293
17293
18283
19283
20283
21273
22273
23274
24264
25264
26264
27264
28264
29264
30264
31265

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 (%)
19640
29640
39730
49730
59730
69820
79820
89820
99820
109820
119910
129910
139910
149910
159910
169910
179910
189910
199910
209910
219910
229910
239910
249910
259910
269910
279910
289910
299910
309811
319811

Wind in December

Winds average 7 mph in December.

Across December, daily wind ranges from about 7 mph on the calmest days to 7 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm
317calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 9 h 30 min at the start of December to 9 h 18 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 7:12 AM to 7:31 AM, and sunset from 4:42 PM to 4:51 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.57:124:42
29.57:134:42
39.57:144:42
49.47:154:42
59.47:164:42
69.47:174:42
79.47:184:42
89.47:194:42
99.47:194:42
109.47:204:42
119.47:214:42
129.37:224:42
139.37:224:43
149.37:234:43
159.37:244:43
169.37:244:43
179.37:254:44
189.37:264:44
199.37:264:44
209.37:274:45
219.37:274:45
229.37:284:46
239.37:284:46
249.37:294:47
259.37:294:47
269.37:294:48
279.37:304:48
289.37:304:49
299.37:304:50
309.37:314:50
319.37:314:51

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 2 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 2 kWh/m² to a high of 6.15 kWh/m² in June across the year — December's 2 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
12.1Moderate
22.1Moderate
32.1Moderate
42.1Moderate
52.1Moderate
62.0Moderate
72.0Moderate
82.0Moderate
92.0Moderate
102.0Dim
112.0Dim
122.0Dim
132.0Dim
141.9Dim
151.9Dim
161.9Dim
171.9Dim
182.0Dim
192.0Dim
202.0Dim
212.0Dim
222.0Dim
232.0Dim
242.0Moderate
252.0Moderate
262.0Moderate
272.0Moderate
282.0Moderate
292.0Moderate
302.0Moderate
312.0Moderate
Planning a trip in December

Hazard calendar for St. Charles

In seasonPeak

None of St. Charles's seasonal hazards are active in December. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.

St. Charles sits in the Atlantic hurricane belt; the season peaks August–October.

Atlantic hurricane
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is December a good time to visit St. Charles?

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

1.8
Sightseeing
10th-best month of the year
0.0
Beach & pool
10th-best month of the year

December is a weaker month for outdoor sightseeing in St. Charles.

What to pack for St. Charles in December

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

In December, St. Charles sees daytime highs around 48°F and nights near 35°F. Pack a warm layer. Worth having: rain gear. About 9 days see rain.

a warm layerrain gear

Sea temperature near St. Charles in December

The nearest coast averages about 45°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 30 mi away) is warmest in August at about 78°F and coldest in February near 37°F.

It's comfortable for a long swim from Jun 16 to Oct 6 — about 3.7 months when the water holds above 68°F.

30°40°50°60°70°80°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°F)Comfort
Jan38Bracing
Feb37Bracing
Mar40Bracing
Apr47Bracing
May57Bracing
Jun68Refreshing
Jul76Warm
Aug78Warm
Sep74Refreshing
Oct65Cool
Nov54Bracing
Dec45Bracing

UV index in St. Charles 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 St. Charles peaks around July 11 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 9 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateLowJul 11UV 9Dec 19UV 2
UV index (midday)Level
Jan2Moderate
Feb3Moderate
Mar5Moderate
Apr6High
May8Very high
Jun9Very high
Jul9Very high
Aug7High
Sep6High
Oct4Moderate
Nov3Moderate
Dec2Low

Air quality in St. Charles 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 St. Charles is worst in July — around 16 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (November, 7 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1416 µg/m³Nov 187 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb10Good
Mar12Good
Apr13Moderate
May14Moderate
Jun15Moderate
Jul16Moderate
Aug14Moderate
Sep11Good
Oct8Good
Nov7Good
Dec8Good
Location & terrain

Where is St. Charles?

St. Charles sits at 38.6°N, 76.9°W, 207 ft above sea level, in United States. The nearest listed city is Saint Charles, 0.6 mi away.

Topography around St. Charles

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

Within 2 miles, the terrain around St. Charles has only modest variations in elevation — a maximum elevation change of 82 ft around an average of 213 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 315 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,539 ft.

The land around St. Charles is covered by trees (58%) and artificial surfaces (30%) within 2 miles, trees (77%) within 10 miles, and trees (59%) and water (21%) within 50 miles.

2 miles
82 ft
10 miles
315 ft
50 miles
1,539 ft
treesgrasslandcroplandartificial surfaceswaterwetland
December weather nearby: Saint Charles 0.6 mi · Waldorf 1.2 mi · Fort Washington 8.7 mi · Clinton 11 mi · Fort Hunt 11 mi · Hybla Valley 13 mi · Oxon Hill-Glassmanor 13 mi · Woodlawn 14 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 St. Charles (38.6073°, -76.9248°, elevation 207 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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). 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).