Koesan weather in December

In December, Koesan sees average daytime highs of 5°C and overnight lows near -4°C, with 26 mm of precipitation across 4.6 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 7°C in the first days to 3°C by the end. The sky is clear or mostly clear about 45% 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 Koesan's 2nd-clearest and 6th-windiest month. For the whole year in context, see Koesan's year-round climate.

Daytime high
11th warmest
Overnight low
-4°
3rd coldest
Precipitation
26 mm
4.6 wet days
Daylight
9 h 30 min
7:40 AM – 5:10 PM
Cloud cover
46%
2nd clearest
Wind
9 km/h
6th windiest
Solar energy
2.37 kWh/m²
Travel score
0.2
out of 10

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 7°C in the first days to 3°C by the end.

A typical December day in Koesan reaches about 5°C in the afternoon and slips back to -4°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between -1°C and 10°C. Set against its neighbours, December runs about 7°C cooler than November and about 2°C warmer than January.

-10°10°151015202531
Avg high (°C)Avg low (°C)
17-1
27-2
37-2
46-2
56-2
66-2
76-3
86-3
95-3
105-3
115-3
125-4
135-4
145-4
154-4
164-4
174-4
184-4
194-4
204-4
214-4
224-5
234-5
244-5
253-5
263-5
273-5
283-5
293-5
303-5
313-5

How December really feels in Koesan

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.

Koesan 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 / -6°234.73.39.80.0
Feb / -4°334.62.110.60.4
Mar11° / 547.12.111.73.0
Apr18° / 837.70.212.96.1
May23° / 12°948013.97.1
Jun27° / 17°1258.8014.56.5
Jul28° / 21°25816.7014.34.8
Aug29° / 22°21915.5013.44.8
Sep25° / 16°1398.9012.26.9
Oct19° / 585.20117.0
Nov12° / 446.60.4103.4
Dec / -4°264.62.19.50.2

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 45% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 17% of December, with mostly cloudy or overcast conditions the remaining 37%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
16139
26139
36139
46139
56238
66238
76139
86238
96238
106139
116238
126238
136238
146238
156337
166238
176337
186337
196337
206436
216436
226436
236436
246436
256436
266436
276535
286535
296436
306436
316436

Chance of precipitation in December

Any precipitationSnow

Koesan gets around 26 mm of rain and snow over 4.6 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 15% and peaks near 19% on the wettest days, and about 2 days bring snow.

0%10%20%30%151015202531
Rain chance (%)Snow chance (%)
1195
2195
3195
4196
5186
6186
7186
8186
9176
10176
11176
12166
13166
14166
15156
16146
17146
18146
19136
20136
21136
22137
23137
24137
25138
26138
27138
28139
29139
30149
31149

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 10 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
2910calm
3010calm
3110calm

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 7:29 AM to 7:47 AM, and sunset from 5:08 PM to 5:17 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.77:295:08
29.67:305:08
39.67:305:08
49.67:315:08
59.67:325:08
69.67:335:08
79.67:345:08
89.67:355:08
99.57:355:08
109.57:365:08
119.57:375:09
129.57:385:09
139.57:385:09
149.57:395:09
159.57:405:09
169.57:405:10
179.57:415:10
189.57:415:10
199.57:425:11
209.57:435:11
219.57:435:12
229.57:445:12
239.57:445:13
249.57:445:13
259.57:455:14
269.57:455:14
279.57:465:15
289.57:465:15
299.57:465:16
309.57:465:17
319.57:475:17

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 2.37 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 2.37 kWh/m² to a high of 5.83 kWh/m² in May across the year — December's 2.37 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
12.4Moderate
22.4Moderate
32.4Moderate
42.4Moderate
52.4Moderate
62.4Moderate
72.4Moderate
82.4Moderate
92.4Moderate
102.4Moderate
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
272.5Moderate
282.5Moderate
292.5Moderate
302.5Moderate
312.5Moderate
Planning a trip in December

Hazard calendar for Koesan

In seasonPeak

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

Koesan'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 Koesan?

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 Koesan.

What to pack for Koesan in December

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

In December, Koesan sees daytime highs around 5°C and nights near -4°C. Pack a warm layer and a heavy coat. About 5 days see rain.

a warm layera heavy coat

UV index in Koesan 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 Koesan peaks around August 14 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 23 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 highHighModerateAug 14UV 9Dec 23UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May7High
Jun7Very high
Jul8Very high
Aug9Very high
Sep8Very high
Oct5High
Nov3Moderate
Dec2Low

Air quality in Koesan 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 Koesan 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 Koesan?

Koesan sits at 36.8°N, 127.8°E, 116 m above sea level, in South Korea. The nearest listed city is Jungpyong, 19 km away.

MungyeongSejongAnseongSangju

Topography around Koesan

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

Within 3 km, the terrain around Koesan has significant variations in elevation — a maximum elevation change of 298 m around an average of 173 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 866 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,408 m.

The land around Koesan is covered by trees (58%) within 3 km, trees (74%) within 16 km, and trees (72%) within 80 km.

3 km
298 m
16 km
866 m
80 km
1,408 m
treesgrasslandcroplandartificial surfacesbare terrainwater
December weather nearby: Jungpyong 19 km · Chungju 22 km · Chinch'ŏn 32 km · Cheongju-si 33 km · Mungyeong 43 km · Sejong 51 km · Anseong 52 km · Sangju 55 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 Koesan (36.8108°, 127.7947°, elevation 116 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).