Sejong weather in December

In December, Sejong sees average daytime highs of 6°C and overnight lows near -3°C, with 23 mm of precipitation across 4.5 wet days and about 9.5 hours of daylight. It is the 11th-warmest and 11th-wettest month of the year here.

Highs ease over the month, from about 8°C in the first days to 4°C by the end. The sky is clear or mostly clear about 35% of the time in December, and the air most often feels dry.

Daylight stretches from about 9 h 42 min at the start of December to 9 h 30 min by month's end. Set against the rest of the year, December is Sejong's 6th-clearest and 7th-windiest month. For the whole year in context, see Sejong's year-round climate.

Daytime high
11th warmest
Overnight low
-3°
3rd coldest
Precipitation
23 mm
4.5 wet days
Daylight
9 h 30 min
7:42 AM – 5:12 PM
Cloud cover
53%
6th clearest
Wind
9 km/h
7th windiest
Solar energy
2.3 kWh/m²
Travel score
0.5
out of 10

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 8°C in the first days to 4°C by the end.

A typical December day in Sejong reaches about 6°C in the afternoon and slips back to -3°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 0°C and 11°C. Set against its neighbours, December runs about 7°C cooler than November and about 2°C warmer than January.

-10°-5°10°15°151015202531
Avg high (°C)Avg low (°C)
18-1
28-1
38-1
48-1
57-1
67-2
77-2
87-2
96-2
106-2
116-2
126-3
136-3
146-3
156-3
165-3
175-3
185-3
195-3
205-3
215-3
225-4
235-4
245-4
255-4
264-4
274-4
284-4
294-4
304-4
314-4

How December really feels in Sejong

Once humidity and wind are folded in, December averages 0 days that feel above 32°C and 31 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
0
heat index over the day's high
Days feeling ≤ C
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.

Sejong 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 (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / -5°224.32.29.80.0
Feb / -3°304.31.510.60.7
Mar12° / 496.71.111.73.6
Apr19° / 797.4012.96.5
May24° / 13°867.5013.97.2
Jun28° / 18°1228.5014.56.1
Jul29° / 22°25616.1014.24.5
Aug30° / 22°22615013.44.4
Sep26° / 17°1438.5012.26.8
Oct20° / 10°584.8011.17.4
Nov13° / 435.90.2104.0
Dec / -3°234.51.49.50.5

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 35% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 20% of December, with mostly cloudy or overcast conditions the remaining 44%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15743
25644
35644
45644
55644
65644
75545
85545
95545
105545
115446
125446
135446
145446
155545
165545
175446
185446
195644
205644
215644
225644
235743
245644
255743
265743
275743
285743
295743
305644
315644

Chance of precipitation in December

Any precipitationSnow

Sejong gets around 23 mm of rain and snow over 4.5 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 15% and peaks near 20% on the wettest days, and about 1 day brings snow. The odds ease toward the end of the month.

0%10%20%30%151015202531
Rain chance (%)Snow chance (%)
1203
2203
3194
4194
5194
6184
7184
8184
9174
10174
11164
12164
13154
14154
15144
16134
17134
18134
19124
20124
21124
22125
23125
24125
25125
26126
27126
28126
29126
30137
31137

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 9 km/h in December.

Across December, daily wind ranges from about 9 km/h on the calmest days to 9 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (km/h)Feels
19calm
29calm
39calm
49calm
59calm
69calm
79calm
89calm
99calm
109calm
119calm
129calm
139calm
149calm
159calm
169calm
179calm
189calm
199calm
209calm
219calm
229calm
239calm
249calm
259calm
269calm
279calm
289calm
299calm
309calm
319calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 9 h 42 min at the start of December to 9 h 30 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 7:30 AM to 7:48 AM, and sunset from 5:11 PM to 5:20 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.77:305:11
29.77:315:11
39.67:325:11
49.67:335:11
59.67:345:11
69.67:345:11
79.67:355:11
89.67:365:11
99.67:375:11
109.67:385:11
119.57:385:11
129.57:395:11
139.57:405:12
149.57:405:12
159.57:415:12
169.57:425:12
179.57:425:13
189.57:435:13
199.57:435:13
209.57:445:14
219.57:445:14
229.57:455:15
239.57:455:15
249.57:465:16
259.57:465:16
269.57:475:17
279.57:475:17
289.57:475:18
299.57:485:19
309.57:485:19
319.57:485:20

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 2.3 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 2.3 kWh/m² to a high of 5.89 kWh/m² in May across the year — December's 2.3 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
12.3Moderate
22.3Moderate
32.3Moderate
42.3Moderate
52.3Moderate
62.3Moderate
72.3Moderate
82.3Moderate
92.3Moderate
102.3Moderate
112.3Moderate
122.3Moderate
132.3Moderate
142.3Moderate
152.3Moderate
162.3Moderate
172.3Moderate
182.3Moderate
192.3Moderate
202.3Moderate
212.3Moderate
222.3Moderate
232.3Moderate
242.3Moderate
252.4Moderate
262.4Moderate
272.4Moderate
282.4Moderate
292.4Moderate
302.4Moderate
312.4Moderate
Planning a trip in December

Hazard calendar for Sejong

In seasonPeak

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

Sejong's rainy season runs June–September, when most of the year's rain falls.

Rainy season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is December a good time to visit Sejong?

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

0.5
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 Sejong.

What to pack for Sejong in December

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

In December, Sejong sees daytime highs around 6°C and nights near -3°C. Pack a warm layer. Worth having: a heavy coat. About 5 days see rain.

a warm layera heavy coat

UV index in Sejong 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 Sejong peaks around August 14 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 23 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 highHighModerateAug 14UV 8Dec 23UV 2
UV index (midday)Level
Jan2Moderate
Feb3Moderate
Mar5Moderate
Apr6High
May7High
Jun7Very high
Jul8Very high
Aug8Very high
Sep8Very high
Oct5High
Nov3Moderate
Dec2Low

Air quality in Sejong 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 Sejong is worst in March — around 80 µg/m³ PM2.5 (unhealthy), about 1.8× the cleanest month (July, 45 µg/m³).

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

0306090JanFebMarAprMayJunJulAugSepOctNovDecUnhealthyPoorUnhealthyMar 1479 µg/m³Jul 2345 µg/m³
PM2.5 (µg/m³)Level
Jan69Unhealthy
Feb72Unhealthy
Mar80Unhealthy
Apr65Unhealthy
May58Unhealthy
Jun54Poor
Jul45Poor
Aug45Poor
Sep56Unhealthy
Oct67Unhealthy
Nov72Unhealthy
Dec65Unhealthy
Location & terrain

Where is Sejong?

Sejong sits at 36.6°N, 127.3°E, 49 m above sea level, in South Korea. The nearest listed city is Cheongju-si, 18 km away.

Seonghwan

Topography around Sejong

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Sejong.

Within 3 km, the terrain around Sejong has only modest variations in elevation — a maximum elevation change of 148 m around an average of 39 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 445 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,213 m.

The land around Sejong is covered by cropland (43%), artificial surfaces (28%) and trees (21%) within 3 km, trees (54%) and cropland (22%) within 16 km, and trees (62%) and cropland (23%) within 80 km.

3 km
148 m
16 km
445 m
80 km
1,213 m
treesgrasslandcroplandartificial surfacesbare terrainwater
December weather nearby: Cheongju-si 18 km · Gongju 21 km · Cheonan 27 km · Daejeon 28 km · Chinch'ŏn 32 km · Asan 33 km · Jungpyong 34 km · Seonghwan 39 km

South Korea travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type C / F
220 V · 60 Hz
Prices
≈ 57% of US
price level, 2025
GDP per capita
$36,227
2025
Happiness
6.0 / 10
World Happiness, 2025
Safe drinking water
99%
of population, 2024
Homicide rate
0.5
per 100k, 2023
Road deaths
8.6
per 100k/yr, 2019
Income group
High
World Bank
English
Moderate
EF EPI 522
Religion
none 60%Protestant 17%Buddhist 16%Catholic 6%

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 Sejong (36.5924°, 127.2922°, elevation 49 m), 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).