Muan weather in September

In September, Muan sees average daytime highs of 27°C and overnight lows near 19°C, with 147 mm of rain across 8.9 wet days and about 12.2 hours of daylight. It is the 3rd-warmest and 4th-wettest month of the year here.

Highs ease over the month, from about 28°C in the first days to 25°C by the end. The sky is clear or mostly clear about 34% of the time in September, and the air most often feels muggy.

Daylight stretches from about 12 h 48 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is Muan's 6th-clearest and 12th-windiest month. For the whole year in context, see Muan's year-round climate.

Daytime high
27°
3rd warmest
Overnight low
19°
10th coldest
Rainfall
147 mm
8.9 wet days
Daylight
12 h 12 min
6:22 AM – 6:35 PM
Cloud cover
57%
6th clearest
Wind
10 km/h
12th windiest
Solar energy
4.41 kWh/m²
Travel score
6.7
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 28°C in the first days to 25°C by the end.

A typical September day in Muan reaches about 27°C in the afternoon and slips back to 19°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 23°C and 30°C. Set against its neighbours, September runs about 4°C cooler than August and about 5°C warmer than October.

10°15°20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
12822
22821
32821
42821
52821
62821
72821
82820
92820
102720
112720
122720
132719
142719
152719
162719
172619
182618
192618
202618
212618
222618
232517
242517
252517
262517
272517
282516
292416
302416

How September really feels in Muan

Once humidity and wind are folded in, September 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

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

Muan weather by month

How September compares with the rest of the year at a glance. September is the 3rd-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / -1°264.629.90.4
Feb / 345.10.910.71.3
Mar12° / 5970.411.73.6
Apr18° / 817.5012.96.1
May23° / 13°927.9013.87.1
Jun26° / 18°1569.4014.36.4
Jul29° / 23°21915.2014.14.8
Aug30° / 24°20614.6013.34.4
Sep27° / 19°1478.9012.26.7
Oct21° / 13°524.3011.17.7
Nov15° / 456010.25.0
Dec / 264.51.49.71.7

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 34% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 16% of September, with mostly cloudy or overcast conditions the remaining 50%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14357
24357
34456
44555
54555
64555
74654
84654
94753
104753
114852
124951
135050
144951
155050
165149
175149
185248
195248
205347
215347
225347
235347
245347
255347
265446
275446
285446
295446
305545

Chance of precipitation in September

Any precipitation

Muan gets around 147 mm of rain over 8.9 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 30% and peaks near 43% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%50%151015202530
Rain chance (%)
143
242
341
440
539
638
737
836
935
1035
1134
1233
1332
1431
1530
1629
1728
1827
1926
2025
2124
2224
2323
2423
2523
2623
2722
2822
2921
3021

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the muggy band about 30% of days. Sticky, muggy-or-worse air turns up on roughly 47% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
10217393210
2121840319
3131940298
4132141287
5142241266
6152341255
7162341244
8272441223
9292540213
103102540202
113122638192
124142637182
134152736161
145172734151
156192733141
167202831131
178222829121
189232828111
191025292691
201226292581
211327292371
221428292261
231629292051
241829291951
252029281841
262230281630
272430281530
282730271420
292930261320
303229251220

Wind in September

Winds average 10 km/h in September, the calmest month.

Across September, daily wind ranges from about 10 km/h on the calmest days to 11 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
111calm
211calm
311calm
411calm
510calm
610calm
710calm
810calm
910calm
1010calm
1110calm
1210calm
1310calm
1410calm
1510calm
1610calm
1710calm
1810calm
1910calm
2010calm
2110calm
2210calm
2310calm
2411calm
2511calm
2611calm
2711calm
2811calm
2911calm
3011calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 48 min at the start of September to 11 h 42 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 66 minutes over September. Sunrise moves from 6:11 AM to 6:33 AM, and sunset from 6:57 PM to 6:14 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.86:116:57
212.76:116:56
312.76:126:54
412.76:136:53
512.66:146:51
612.66:146:50
712.66:156:48
812.56:166:47
912.56:176:45
1012.46:176:44
1112.46:186:42
1212.46:196:41
1312.36:206:39
1412.36:206:38
1512.36:216:36
1612.26:226:35
1712.26:236:33
1812.16:236:32
1912.16:246:30
2012.16:256:29
2112.06:266:27
2212.06:266:26
2312.06:276:24
2411.96:286:23
2511.96:296:21
2611.86:306:20
2711.86:306:18
2811.86:316:17
2911.76:326:16
3011.76:336:14

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.41 kWh/m².

For context, solar energy here swings from a low near 2.23 kWh/m² to a high of 5.91 kWh/m² in May across the year — September's 4.41 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.6Bright
24.6Bright
34.6Bright
44.5Bright
54.5Bright
64.5Bright
74.5Bright
84.5Bright
94.5Bright
104.5Bright
114.5Bright
124.4Bright
134.4Bright
144.4Bright
154.4Bright
164.4Bright
174.4Bright
184.4Bright
194.4Bright
204.3Bright
214.3Bright
224.3Bright
234.3Bright
244.3Bright
254.3Bright
264.3Bright
274.2Bright
284.2Bright
294.2Bright
304.2Bright
Planning a trip in September

Hazard calendar for Muan

In seasonPeak

In September, Muan sits inside its pacific typhoon and rainy season season. The full year is below, with each hazard's peak months called out.

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

Muan'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 September a good time to visit Muan?

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

6.7
Sightseeing
3rd-best month of the year
6.6
Beach & pool
1st-best month of the year

September is a reasonable time to visit Muan for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Muan in September

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

In September, Muan sees daytime highs around 27°C and nights near 19°C. Worth packing: light clothes and rain gear. About 9 days see rain.

light clothesrain gear

Sea temperature near Muan in September

The nearest coast averages about 23°C in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 36 km away) is warmest in August at about 25°C and coldest in February near 7°C.

It's comfortable for a long swim from Jun 28 to Oct 9 — about 3.4 months when the water holds above 20°C.

10°20°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan8Bracing
Feb7Bracing
Mar7Bracing
Apr10Bracing
May14Bracing
Jun19Cool
Jul22Refreshing
Aug25Warm
Sep23Refreshing
Oct19Cool
Nov15Cool
Dec11Bracing

UV index in Muan in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 8 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Muan peaks around June 21 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 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 highHighModerateJun 21UV 8Dec 22UV 2
UV index (midday)Level
Jan2Moderate
Feb3Moderate
Mar6High
Apr7High
May8Very high
Jun8Very high
Jul8Very high
Aug8Very high
Sep8Very high
Oct6High
Nov4Moderate
Dec2Moderate

Air quality in Muan in September

GoodModeratePoorUnhealthyVery unhealthy

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

Air quality in Muan is worst in March — around 61 µg/m³ PM2.5 (unhealthy), about 2.1× the cleanest month (August, 28 µg/m³).

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

020406080JanFebMarAprMayJunJulAugSepOctNovDecPoorUnhealthyPoorModeratePoorModerateMar 1960 µg/m³Aug 1129 µg/m³
PM2.5 (µg/m³)Level
Jan41Poor
Feb48Poor
Mar61Unhealthy
Apr54Poor
May45Poor
Jun39Poor
Jul29Moderate
Aug28Moderate
Sep33Moderate
Oct35Moderate
Nov38Poor
Dec34Moderate
Location & terrain

Where is Muan?

Muan sits at 35.0°N, 126.5°E, 21 m above sea level, in South Korea. The nearest listed city is Mokpo, 21 km away.

MasanSinanGwangjuJangseong

Topography around Muan

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

Within 3 km, the terrain around Muan has significant variations in elevation — a maximum elevation change of 284 m around an average of 55 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 345 m; within 80 km, large variations in elevation — a maximum elevation change of 1,171 m.

The land around Muan is covered by trees (52%) and cropland (31%) within 3 km, cropland (36%), trees (33%) and water (20%) within 16 km, and water (45%) and trees (34%) within 80 km.

3 km
284 m
16 km
345 m
80 km
1,171 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Mokpo 21 km · Naju 22 km · Yeongam 29 km · Yeonggwang 32 km · Masan 36 km · Sinan 38 km · Gwangju 44 km · Jangseong 44 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 Muan (34.9901°, 126.479°, elevation 21 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).