Koesan weather in April

In April, Koesan sees average daytime highs of 18°C and overnight lows near 6°C, with 83 mm of precipitation across 7.7 wet days and about 12.9 hours of daylight. It is the 7th-warmest and 6th-wettest month of the year here.

Highs climb over the month, from about 15°C in the first days to 21°C by the end. The sky is clear or mostly clear about 40% of the time in April, and the air most often feels dry.

Daylight stretches from about 12 h 24 min at the start of April to 13 h 30 min by month's end. Set against the rest of the year, April is Koesan's 6th-clearest and 1st-windiest month. For the whole year in context, see Koesan's year-round climate.

Daytime high
18°
7th warmest
Overnight low
6th coldest
Precipitation
83 mm
7.7 wet days
Daylight
12 h 54 min
6:01 AM – 6:57 PM
Cloud cover
52%
6th clearest
Wind
10 km/h
1st windiest
Solar energy
5.44 kWh/m²
Travel score
6.1
out of 10

Temperature in April

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 15°C in the first days to 21°C by the end.

A typical April day in Koesan reaches about 18°C in the afternoon and slips back to 6°C overnight — a 12°C spread between the day's warmth and the night's chill. On most days the high lands between 12°C and 24°C. Set against its neighbours, April runs about 7°C warmer than March and about 5°C cooler than May.

10°20°30°151015202530
Avg high (°C)Avg low (°C)
1153
2153
3154
4154
5164
6164
7164
8165
9175
10175
11175
12175
13186
14186
15186
16186
17186
18197
19197
20197
21197
22197
23208
24208
25208
26208
27209
28219
29219
30219

How April really feels in Koesan

Once humidity and wind are folded in, April averages 0 days that feel above 32°C and 0 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
0
wind chill below the day's low

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

Koesan weather by month

How April compares with the rest of the year at a glance. April is the 7th-warmest and 6th-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 April

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 40% of the time in April.

Beyond those clear spells, partly cloudy skies cover about 15% of April, with mostly cloudy or overcast conditions the remaining 45%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15644
25644
35644
45644
55644
65644
75743
85743
95743
105743
115743
125644
135545
145545
155545
165446
175446
185446
195446
205446
215347
225446
235446
245347
255446
265347
275446
285347
295347
305446

Chance of precipitation in April

Any precipitationSnow

Koesan gets around 83 mm of rain and snow over 7.7 wet days in April. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 25% and peaks near 28% on the wettest days, and about 0 day brings snow.

0%10%20%30%40%151015202530
Rain chance (%)Snow chance (%)
1232
2232
3242
4241
5241
6241
7241
8241
9241
10241
11241
12251
13251
14251
15250
16250
17250
18260
19260
20260
21260
22260
23270
24270
25270
26270
27280
28280
29280
30280

Humidity in April

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, April lands in the dry band about 97% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)
110000
210000
310000
410000
510000
610000
710000
89910
99910
109910
119910
129910
139910
149910
159820
169820
179820
189721
199721
209631
219631
229631
239541
249541
259451
269451
279361
289361
299172
309172

Wind in April

Winds average 10 km/h in April, the windiest month of the year.

Across April, daily wind ranges from about 10 km/h on the calmest days to 10 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
110calm
210calm
310calm
410calm
510calm
610calm
710calm
810calm
910calm
1010calm
1110calm
1210calm
1310calm
1410calm
1510calm
1610calm
1710calm
1810calm
1910calm
2010calm
2110calm
2210calm
2310calm
2410calm
2510calm
2610calm
2710calm
2810calm
2910calm
3010calm

Sunrise & sunset in April

DaylightNight

Daylight runs from about 12 h 24 min at the start of April to 13 h 30 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 66 minutes over April. Sunrise moves from 6:23 AM to 5:43 AM, and sunset from 6:44 PM to 7:10 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.46:236:44
212.46:216:45
312.46:206:46
412.56:186:47
512.56:176:48
612.66:156:48
712.66:146:49
812.66:126:50
912.76:116:51
1012.76:096:52
1112.76:086:53
1212.86:076:54
1312.86:056:55
1412.96:046:55
1512.96:026:56
1612.96:016:57
1713.05:596:58
1813.05:586:59
1913.15:577:00
2013.15:557:01
2113.15:547:02
2213.25:537:03
2313.25:517:03
2413.25:507:04
2513.35:497:05
2613.35:477:06
2713.35:467:07
2813.45:457:08
2913.45:447:09
3013.55:437:10

Solar energy in April

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in April, about 5.44 kWh/m².

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 — April's 5.44 kWh/m² sits near the top of that range.

0246151015202530
Solar energy (kWh/m²)Level
15.2Bright
25.2Bright
35.2Bright
45.2Bright
55.3Bright
65.3Bright
75.3Bright
85.3Bright
95.3Bright
105.4Bright
115.4Bright
125.4Bright
135.4Bright
145.4Bright
155.5Bright
165.5Bright
175.5Bright
185.5Bright
195.5Bright
205.5Bright
215.5Bright
225.5Bright
235.6Bright
245.6Bright
255.6Bright
265.6Bright
275.6Bright
285.6Bright
295.6Bright
305.6Bright
Planning a trip in April

Hazard calendar for Koesan

In seasonPeak

None of Koesan's seasonal hazards are active in April. 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 April a good time to visit Koesan?

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

6.1
Sightseeing
5th-best month of the year
2.1
Beach & pool
7th-best month of the year

April is a reasonable time to visit Koesan for sightseeing.

What to pack for Koesan in April

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

In April, Koesan sees daytime highs around 18°C and nights near 6°C. Worth packing: a warm layer and sun protection. About 8 days see rain.

a warm layersun protection

UV index in Koesan in April

LowModerateHighVery highExtreme

Clear-sky midday UV in April peaks around 6 — enough to warrant sun protection. 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 April

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where April 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
April 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).