Sumter weather in December

In December, Sumter sees average daytime highs of 59°F and overnight lows near 40°F, with 3.7 in of precipitation across 8.6 wet days and about 9.8 hours of daylight. It is the 11th-warmest and 5th-wettest month of the year here.

Highs ease over the month, from about 61°F in the first days to 57°F by the end. The sky is clear or mostly clear about 38% of the time in December, and the air most often feels dry.

Daylight stretches from about 9 h 54 min at the start of December to 9 h 48 min by month's end. Set against the rest of the year, December is Sumter's 6th-clearest and 5th-windiest month. For the whole year in context, see Sumter's year-round climate.

Daytime high
59°
11th warmest
Overnight low
40°
2nd coldest
Precipitation
3.7 in
8.6 wet days
Daylight
9 h 48 min
7:25 AM – 5:10 PM
Cloud cover
55%
6th clearest
Wind
8 mph
5th windiest
Solar energy
2.42 kWh/m²
Travel score
4.7
out of 10

Sumter is city in and county seat of Sumter County, South Carolina, United States.

Density
491/km²
people per km²
Founded
1845

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 61°F in the first days to 57°F by the end.

A typical December day in Sumter reaches about 59°F in the afternoon and slips back to 40°F overnight — a 19°F spread between the day's warmth and the night's chill. On most days the high lands between 45°F and 72°F. Set against its neighbours, December runs about 7°F cooler than November and about 2°F warmer than January.

20°40°60°80°151015202531
Avg high (°F)Avg low (°F)
16242
26242
36141
46141
56141
66041
76040
86040
96040
105940
115940
125940
135940
145940
155839
165839
175839
185839
195839
205839
215839
225839
235739
245739
255739
265739
275738
285738
295738
305738
315738

How December really feels in Sumter

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

December sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Sumter weather by month

How December compares with the rest of the year at a glance. December is the 11th-warmest and 5th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan56° / 37°3.58.90.5104.1
Feb60° / 40°3.38.60.310.74.9
Mar67° / 46°3.49.40.111.76.4
Apr76° / 54°3.48012.87.2
May82° / 63°3.19.5013.76.2
Jun88° / 71°4.213.2014.24.1
Jul91° / 74°4.715.50143.2
Aug89° / 73°4.714.5013.33.7
Sep84° / 67°4.210012.25.6
Oct75° / 56°3.37.6011.17.4
Nov66° / 45°2.87.2010.26.6
Dec59° / 40°3.78.60.19.84.7

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 38% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 11% of December, with mostly cloudy or overcast conditions the remaining 51%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15347
25347
35248
45149
55248
65149
75050
85149
95050
105050
115050
125050
135050
145050
155050
165050
175050
185050
194852
204852
214852
224852
234753
244654
254753
264654
274555
284555
294555
304555
314555

Chance of precipitation in December

Any precipitation

Sumter gets around 3.7 in of rain and snow over 8.6 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 0 day brings snow.

0%10%20%30%40%151015202531
Rain chance (%)
126
226
326
427
527
627
727
827
927
1028
1128
1228
1328
1428
1528
1629
1729
1829
1929
2029
2129
2229
2329
2429
2529
2629
2730
2830
2930
3029
3129

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 89% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)
187751
287751
387751
488741
589740
689740
789740
890730
990730
1090730
1190730
1290730
1390730
1490730
1591720
1690721
1790721
1890721
1990721
2090721
2189722
2289722
2388732
2488732
2588732
2688732
2788732
2888732
2988732
3087832
3187832

Wind in December

Winds average 8 mph in December.

Across December, daily wind ranges from about 7 mph on the calmest days to 8 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
17light breeze
27light breeze
37light breeze
47light breeze
57light breeze
67light 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 54 min at the start of December to 9 h 48 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 6 minutes over December. Sunrise moves from 7:14 AM to 7:31 AM, and sunset from 5:08 PM to 5:18 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.97:145:08
29.97:155:08
39.97:165:08
49.97:165:08
59.87:175:08
69.87:185:08
79.87:195:08
89.87:205:08
99.87:205:09
109.87:215:09
119.87:225:09
129.87:225:09
139.87:235:09
149.87:245:10
159.87:245:10
169.87:255:10
179.77:265:10
189.77:265:11
199.77:275:11
209.77:275:12
219.77:285:12
229.77:285:13
239.77:295:13
249.77:295:14
259.77:295:14
269.77:305:15
279.77:305:15
289.87:315:16
299.87:315:16
309.87:315:17
319.87:315:18

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 2.42 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 2.42 kWh/m² to a high of 6.2 kWh/m² in June across the year — December's 2.42 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
12.6Moderate
22.6Moderate
32.6Moderate
42.6Moderate
52.5Moderate
62.5Moderate
72.5Moderate
82.5Moderate
92.5Moderate
102.5Moderate
112.4Moderate
122.4Moderate
132.4Moderate
142.4Moderate
152.4Moderate
162.4Moderate
172.4Moderate
182.4Moderate
192.4Moderate
202.4Moderate
212.4Moderate
222.4Moderate
232.4Moderate
242.4Moderate
252.4Moderate
262.4Moderate
272.4Moderate
282.4Moderate
292.4Moderate
302.4Moderate
312.4Moderate
Planning a trip in December

Is December a good time to visit Sumter?

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

4.7
Sightseeing
8th-best month of the year
0.3
Beach & pool
11th-best month of the year

December is a reasonable time to visit Sumter for sightseeing.

What to pack for Sumter in December

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

In December, Sumter sees daytime highs around 59°F and nights near 40°F. Worth packing: a warm layer and rain gear. About 9 days see rain.

a warm layerrain gear

UV index in Sumter in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 3. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Sumter peaks around July 13 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 20 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 11 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateJul 13UV 9Dec 20UV 3
UV index (midday)Level
Jan3Moderate
Feb5Moderate
Mar6High
Apr7High
May8Very high
Jun9Very high
Jul9Very high
Aug8Very high
Sep7Very high
Oct5Moderate
Nov4Moderate
Dec3Moderate

Air quality in Sumter 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 Sumter is worst in March — around 18 µg/m³ PM2.5 (moderate), about 2.3× the cleanest month (December, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1518 µg/m³Dec 178 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb11Good
Mar18Moderate
Apr13Moderate
May13Moderate
Jun17Moderate
Jul18Moderate
Aug16Moderate
Sep12Good
Oct9Good
Nov8Good
Dec8Good
Location & terrain

Where is Sumter?

Sumter sits at 33.9°N, 80.3°W, 171 ft above sea level, in United States. The nearest listed city is Florence, 38 mi away.

Topography around Sumter

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

Within 2 miles, the terrain around Sumter has only modest variations in elevation — a maximum elevation change of 98 ft around an average of 171 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 305 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,079 ft.

The land around Sumter is covered by trees (63%) and artificial surfaces (25%) within 2 miles, trees (64%) within 10 miles, and trees (75%) within 50 miles.

2 miles
98 ft
10 miles
305 ft
50 miles
1,079 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
December weather nearby: Florence 38 mi · Columbia 40 mi · West Columbia 42 mi · Saint Andrews 44 mi · Seven Oaks 47 mi · Lexington 52 mi · Summerville 63 mi · Goose Creek 67 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 Sumter (33.9204°, -80.3415°, elevation 171 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).