Ulsan weather in April

In April, Ulsan sees average daytime highs of 18°C and overnight lows near 8°C, with 92 mm of rain across 7.6 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 16°C in the first days to 20°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 18 min at the start of April to 13 h 24 min by month's end. Set against the rest of the year, April is Ulsan's 7th-clearest and 5th-windiest month. For the whole year in context, see Ulsan's year-round climate.

Daytime high
18°
7th warmest
Overnight low
6th coldest
Rainfall
92 mm
7.6 wet days
Daylight
12 h 54 min
5:56 AM – 6:50 PM
Cloud cover
54%
7th clearest
Wind
12 km/h
5th windiest
Solar energy
5.51 kWh/m²
Travel score
6.3
out of 10
Air quality
Elevated
PM2.5 17 µg/m³ · 2020

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

Temperature in April

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 16°C in the first days to 20°C by the end.

A typical April day in Ulsan reaches about 18°C in the afternoon and slips back to 8°C overnight — a 10°C spread between the day's warmth and the night's chill. On most days the high lands between 14°C and 23°C. Set against its neighbours, April runs about 5°C warmer than March and about 4°C cooler than May.

10°20°30°151015202530
Avg high (°C)Avg low (°C)
1166
2166
3166
4176
5176
6177
7177
8177
9177
10187
11188
12188
13188
14188
15188
16198
17199
18199
19199
20199
21199
22209
232010
242010
252010
262010
272010
282011
292111
302111

How April really feels in Ulsan

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.

Ulsan 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 / -1°314.40.79.91.0
Feb / 3950.910.72.0
Mar13° / 717.40.511.74.0
Apr18° / 927.6012.96.3
May23° / 13°1007.8013.87.1
Jun25° / 18°1439.1014.46.7
Jul28° / 23°21613.3014.25.3
Aug29° / 23°21314.2013.34.9
Sep25° / 19°17310.4012.26.6
Oct21° / 13°735.1011.17.4
Nov15° / 484.90.110.15.4
Dec / 273.60.39.62.2

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 12% of April, with mostly cloudy or overcast conditions the remaining 48%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15248
25248
35248
45248
55248
65248
75248
85248
95248
105248
115248
125248
135248
145248
155248
165248
175347
185347
195347
205347
215347
225347
235149
245149
255149
265050
274951
285050
295050
304951

Chance of precipitation in April

Any precipitation

Ulsan gets around 92 mm of rain over 7.6 wet days in April. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 25% and peaks near 27% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
124
224
324
424
523
623
723
823
923
1023
1124
1224
1324
1425
1525
1625
1726
1826
1926
2026
2126
2227
2327
2427
2527
2627
2727
2826
2926
3026

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 95% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)
19910
29910
39910
49910
59910
69910
79820
89820
99820
109820
119820
129820
139820
149820
159631
169631
179631
189631
199631
209541
219541
229451
239352
249262
259172
269082
278983
288893
2987103
3086113

Wind in April

Winds average 12 km/h in April.

Across April, daily wind ranges from about 12 km/h on the calmest days to 12 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
112calm
212calm
312calm
412calm
512calm
612calm
712calm
812calm
912calm
1012calm
1112calm
1212calm
1312calm
1412calm
1512calm
1612calm
1712calm
1812calm
1912calm
2012calm
2112calm
2212calm
2312calm
2412calm
2512calm
2612calm
2712calm
2812calm
2912calm
3012calm

Sunrise & sunset in April

DaylightNight

Daylight runs from about 12 h 18 min at the start of April to 13 h 24 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 6:17 AM to 5:38 AM, and sunset from 6:37 PM to 7:02 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.36:176:37
212.46:166:38
312.46:146:39
412.46:136:40
512.56:116:41
612.56:106:42
712.66:096:42
812.66:076:43
912.66:066:44
1012.76:046:45
1112.76:036:46
1212.86:026:47
1312.86:006:47
1412.85:596:48
1512.95:576:49
1612.95:566:50
1712.95:556:51
1813.05:536:52
1913.05:526:52
2013.05:516:53
2113.15:496:54
2213.15:486:55
2313.15:476:56
2413.25:466:57
2513.25:446:57
2613.35:436:58
2713.35:426:59
2813.35:417:00
2913.45:407:01
3013.45:387:02

Solar energy in April

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in April, about 5.51 kWh/m².

For context, solar energy here swings from a low near 2.65 kWh/m² to a high of 5.9 kWh/m² in May across the year — April's 5.51 kWh/m² sits near the top of that range.

0246151015202530
Solar energy (kWh/m²)Level
15.2Bright
25.2Bright
35.2Bright
45.3Bright
55.3Bright
65.3Bright
75.3Bright
85.4Bright
95.4Bright
105.4Bright
115.4Bright
125.5Bright
135.5Bright
145.5Bright
155.5Bright
165.5Bright
175.5Bright
185.6Bright
195.6Bright
205.6Bright
215.6Bright
225.6Bright
235.6Bright
245.7Bright
255.7Bright
265.7Bright
275.7Bright
285.7Bright
295.7Bright
305.7Bright
Planning a trip in April

Hazard calendar for Ulsan

In seasonPeak

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

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

Ulsan's rainy season runs May–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 April a good time to visit Ulsan?

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

6.3
Sightseeing
5th-best month of the year
2.4
Beach & pool
7th-best month of the year

April is a reasonable time to visit Ulsan for sightseeing.

What to pack for Ulsan in April

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

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

sun protection

Sea temperature near Ulsan in April

The nearest coast averages about 15°C in April — 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 26°C and coldest in February near 14°C.

It's comfortable for a long swim from Jun 17 to Nov 9 — about 4.8 months when the water holds above 20°C.

10°15°20°25°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan15Bracing
Feb14Bracing
Mar14Bracing
Apr15Bracing
May17Cool
Jun20Refreshing
Jul23Refreshing
Aug26Warm
Sep25Warm
Oct22Refreshing
Nov20Cool
Dec17Cool

UV index in Ulsan in April

LowModerateHighVery highExtreme

Clear-sky midday UV in April peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Ulsan peaks around August 17 at about 9 (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 highModerateAug 17UV 9Dec 23UV 2
UV index (midday)Level
Jan2Moderate
Feb4Moderate
Mar5High
Apr7High
May8Very high
Jun8Very high
Jul9Very high
Aug9Very high
Sep9Very high
Oct5High
Nov4Moderate
Dec2Moderate

Air quality in Ulsan 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 Ulsan is worst in March — around 21 µg/m³ PM2.5 (moderate), about 1.6× the cleanest month (August, 13 µg/m³).

Seasonal pattern from CAMS reanalysis, scaled to Ulsan's WHO annual average of 17 µg/m³.

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateMar 2121 µg/m³Aug 1913 µg/m³
PM2.5 (µg/m³)Level
Jan16Moderate
Feb18Moderate
Mar21Moderate
Apr21Moderate
May20Moderate
Jun17Moderate
Jul14Moderate
Aug13Moderate
Sep14Moderate
Oct16Moderate
Nov18Moderate
Dec15Moderate
Location & terrain

Where is Ulsan?

Ulsan sits at 35.5°N, 129.3°E, 10 m above sea level, in South Korea. The nearest listed city is Ungsang, 20 km away.

GijangGyeongjuMiryangKimhaeYeonilPohang

Topography around Ulsan

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

Within 3 km, the terrain around Ulsan has only modest variations in elevation — a maximum elevation change of 136 m around an average of 26 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 752 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,204 m.

The land around Ulsan is covered by artificial surfaces (61%) and trees (30%) within 3 km, trees (55%) within 16 km, and trees (44%) and water (40%) within 80 km.

3 km
136 m
16 km
752 m
80 km
1,204 m
treesgrasslandcroplandartificial surfacesbare terrainwater
April weather nearby: Ungsang 20 km · Yangsan 34 km · Gijang 34 km · Gyeongju 35 km · Miryang 52 km · Kimhae 52 km · Yeonil 52 km · Pohang 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 Ulsan (35.5372°, 129.3167°, elevation 10 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).