Seosan weather in January

In January, Seosan sees average daytime highs of 3°C and overnight lows near -3°C, with 22 mm of precipitation across 4.9 wet days and about 9.8 hours of daylight. It is the 12th-warmest and 12th-wettest month of the year here.

Day-to-day highs hold fairly steady near 3°C through the month. The sky is clear or mostly clear about 23% of the time in January, and the air most often feels dry.

Daylight stretches from about 9 h 30 min at the start of January to 10 h 06 min by month's end. Set against the rest of the year, January is Seosan's 11th-clearest and 1st-windiest month. For the whole year in context, see Seosan's year-round climate.

Daytime high
12th warmest
Overnight low
-3°
1st coldest
Precipitation
22 mm
4.9 wet days
Daylight
9 h 42 min
7:51 AM – 5:36 PM
Cloud cover
65%
11th clearest
Wind
14 km/h
1st windiest
Solar energy
2.47 kWh/m²
Travel score
0.0
out of 10

Seosan is city in South Korea.

Density
100/km²
people per km²

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in January

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 3°C through the month.

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

-10°-5°10°151015202531
Avg high (°C)Avg low (°C)
14-2
24-2
33-2
43-2
53-2
63-2
73-2
83-2
93-2
103-3
113-3
123-3
133-3
143-3
153-3
163-3
173-3
183-3
193-3
203-3
213-3
223-3
233-3
243-3
253-3
263-3
273-3
283-3
293-3
303-3
313-3

How January really feels in Seosan

Once humidity and wind are folded in, January 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 January is cold — wind chill drags the overnight "feels like" below the raw low.

Seosan weather by month

How January compares with the rest of the year at a glance. January is the 12th-warmest and 12th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / -3°224.949.80.0
Feb / -2°274.21.710.60.2
Mar10° / 415.60.911.72.4
Apr16° / 696.8012.95.3
May21° / 13°797013.97.0
Jun25° / 18°1167.7014.57.1
Jul27° / 22°24514.8014.35.4
Aug29° / 23°22513.7013.45.3
Sep25° / 18°1337.5012.27.2
Oct20° / 12°555.30117.1
Nov12° / 497.20.4103.6
Dec / -0°266.13.49.50.4

Cloud cover in January

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 23% of the time in January.

Beyond those clear spells, partly cloudy skies cover about 17% of January, with mostly cloudy or overcast conditions the remaining 60%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14060
24060
34060
43961
53862
63862
73862
83862
93862
103763
113763
123862
133763
143763
153862
163763
173763
183862
193961
203961
214060
224159
234159
244357
254357
264555
274555
284555
294753
304753
314753

Chance of precipitation in January

Any precipitationSnow

Seosan gets around 22 mm of rain and snow over 4.9 wet days in January, the driest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 16% and peaks near 17% on the wettest days, and about 4 days bring snow.

0%10%20%30%151015202531
Rain chance (%)Snow chance (%)
11713
21713
31613
41613
51613
61513
71513
81512
91512
101512
111512
121612
131612
141612
151612
161613
171713
181713
191713
201713
211713
221713
231613
241613
251513
261513
271412
281412
291311
301311
311210

Humidity in January

DryComfortableHumidMuggyOppressiveMiserable

Most of January feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, January 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 January

Winds average 14 km/h in January, the windiest month of the year.

Across January, daily wind ranges from about 14 km/h on the calmest days to 14 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202531
Wind speed (km/h)Feels
114light breeze
214light breeze
314light breeze
414light breeze
514light breeze
614light breeze
714light breeze
814light breeze
914light breeze
1014light breeze
1114light breeze
1214light breeze
1314light breeze
1414light breeze
1514light breeze
1614light breeze
1714light breeze
1814light breeze
1914light breeze
2014light breeze
2114light breeze
2214light breeze
2314light breeze
2414light breeze
2514light breeze
2614light breeze
2714light breeze
2814light breeze
2914light breeze
3014light breeze
3114light breeze

Sunrise & sunset in January

DaylightNight

Daylight runs from about 9 h 30 min at the start of January to 10 h 06 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 36 minutes over January. Sunrise moves from 7:52 AM to 7:44 AM, and sunset from 5:23 PM to 5:51 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.57:525:23
29.57:525:24
39.57:525:24
49.67:525:25
59.67:525:26
69.67:525:27
79.67:525:28
89.67:525:28
99.67:525:29
109.67:525:30
119.67:525:31
129.77:525:32
139.77:525:33
149.77:525:34
159.77:525:35
169.77:515:36
179.87:515:37
189.87:515:38
199.87:505:39
209.87:505:40
219.87:505:41
229.97:495:42
239.97:495:43
249.97:485:44
259.97:485:45
2610.07:475:46
2710.07:475:47
2810.07:465:48
2910.17:455:49
3010.17:455:50
3110.17:445:51

Solar energy in January

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in January, about 2.47 kWh/m².

For context, solar energy here swings from a low near 2.15 kWh/m² to a high of 5.95 kWh/m² in May across the year — January's 2.47 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
12.2Moderate
22.2Moderate
32.2Moderate
42.2Moderate
52.3Moderate
62.3Moderate
72.3Moderate
82.3Moderate
92.3Moderate
102.3Moderate
112.3Moderate
122.3Moderate
132.4Moderate
142.4Moderate
152.4Moderate
162.4Moderate
172.5Moderate
182.5Moderate
192.5Moderate
202.5Moderate
212.6Moderate
222.6Moderate
232.6Moderate
242.7Moderate
252.7Moderate
262.8Moderate
272.8Moderate
282.8Moderate
292.9Moderate
302.9Moderate
313.0Moderate
Planning a trip in January

Hazard calendar for Seosan

In seasonPeak

In January, Seosan sits inside its pacific typhoon season. The full year is below, with each hazard's peak months called out.

Seosan sits in the Pacific typhoon belt; the season peaks July–October.

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

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

Is January a good time to visit Seosan?

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

0.0
Sightseeing
12th-best month of the year
0.0
Beach & pool
10th-best month of the year

January is a weaker month for outdoor sightseeing in Seosan.

What to pack for Seosan in January

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

In January, Seosan sees daytime highs around 3°C and nights near -3°C. Pack a warm layer and a heavy coat. About 5 days see rain.

a warm layera heavy coat

Sea temperature near Seosan in January

The nearest coast averages about 7°C in January — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 19 km away) is warmest in August at about 25°C and coldest in February near 5°C.

It's comfortable for a long swim from Jul 4 to Oct 7 — about 3.2 months when the water holds above 20°C.

0°10°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan7Bracing
Feb5Bracing
Mar6Bracing
Apr8Bracing
May12Bracing
Jun18Cool
Jul22Refreshing
Aug25Warm
Sep23Refreshing
Oct19Cool
Nov15Cool
Dec11Bracing

UV index in Seosan in January

LowModerateHighVery highExtreme

Clear-sky midday UV in January peaks around 2. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Seosan peaks around July 20 at about 7 (very high) — sunscreen and a hat are worth it in the middle of the day. 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 highHighModerateJul 20UV 7Dec 23UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May6High
Jun7High
Jul8Very high
Aug7Very high
Sep7Very high
Oct5High
Nov3Moderate
Dec2Low

Air quality in Seosan in January

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where January falls, not just the annual average.

Air quality in Seosan is worst in March — around 92 µg/m³ PM2.5 (unhealthy), about 2.0× the cleanest month (July, 46 µg/m³).

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

0306090120JanFebMarAprMayJunJulAugSepOctNovDecUnhealthyPoorUnhealthyMar 1391 µg/m³Jul 2246 µg/m³
PM2.5 (µg/m³)Level
Jan83Unhealthy
Feb85Unhealthy
Mar92Unhealthy
Apr75Unhealthy
May62Unhealthy
Jun57Unhealthy
Jul46Poor
Aug47Poor
Sep61Unhealthy
Oct74Unhealthy
Nov79Unhealthy
Dec73Unhealthy
Location & terrain

Where is Seosan?

Seosan sits at 36.8°N, 126.5°E, 33 m above sea level, in South Korea. The nearest listed city is Tangjin, 20 km away.

YesanAsanBoryeongHwaseong-siPyeongtaek

Topography around Seosan

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

Within 3 km, the terrain around Seosan has only modest variations in elevation — a maximum elevation change of 192 m around an average of 43 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 643 m; within 80 km, large variations in elevation — a maximum elevation change of 769 m.

The land around Seosan is covered by cropland (33%), trees (30%) and artificial surfaces (30%) within 3 km, cropland (39%) and trees (38%) within 16 km, and water (53%) and trees (25%) within 80 km.

3 km
192 m
16 km
643 m
80 km
769 m
treesgrasslandcroplandartificial surfaceswaterwetland
January weather nearby: Tangjin 20 km · Taesal-li 21 km · Hongseong 28 km · Yesan 37 km · Asan 49 km · Boryeong 50 km · Hwaseong-si 57 km · Pyeongtaek 61 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 Seosan (36.7817°, 126.4522°, elevation 33 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. 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).