Yeosu weather in September

In September, Yeosu sees average daytime highs of 24°C and overnight lows near 21°C, with 160 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 26°C in the first days to 23°C by the end. The sky is clear or mostly clear about 37% 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 Yeosu's 8th-clearest and 6th-windiest month. For the whole year in context, see Yeosu's year-round climate.

Daytime high
24°
3rd warmest
Overnight low
21°
10th coldest
Rainfall
160 mm
8.9 wet days
Daylight
12 h 12 min
6:17 AM – 6:30 PM
Cloud cover
55%
8th clearest
Wind
16 km/h
6th windiest
Solar energy
4.32 kWh/m²
Travel score
7.0
out of 10

Yeosu is city in South Korea.

Density
534/km²
people per km²
Founded
~940 CE

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

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 26°C in the first days to 23°C by the end.

A typical September day in Yeosu reaches about 24°C in the afternoon and slips back to 21°C overnight — a 3°C spread between the day's warmth and the night's chill. On most days the high lands between 22°C and 26°C. Set against its neighbours, September runs about 3°C cooler than August and about 5°C warmer than October.

15°20°25°30°151015202530
Avg high (°C)Avg low (°C)
12623
22623
32623
42623
52623
62623
72523
82523
92522
102522
112522
122522
132522
142522
152422
162421
172421
182421
192421
202421
212421
222420
232320
242320
252320
262320
272320
282319
292319
302219

How September really feels in Yeosu

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.

Yeosu 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 daysDaylight (hours)Travel score
Jan / 344.39.90.6
Feb / 484.810.71.3
Mar11° / 927.411.72.8
Apr15° / 11°1348.512.84.5
May18° / 16°1478.413.86.2
Jun22° / 20°1949.414.36.4
Jul25° / 23°26813.614.16.1
Aug27° / 25°22412.613.36.2
Sep24° / 21°1608.912.27.0
Oct20° / 16°714.711.17.3
Nov14° / 10°505.410.24.7
Dec / 313.99.71.9

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 37% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 15% of September, with mostly cloudy or overcast conditions the remaining 48%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14654
24753
34654
44753
54852
64852
74951
84852
94951
105050
115149
125050
135149
145149
155149
165347
175347
185347
195347
205545
215545
225545
235545
245545
255644
265743
275743
285743
295842
305842

Chance of precipitation in September

Any precipitation

Yeosu gets around 160 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 39% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%50%151015202530
Rain chance (%)
139
238
337
436
536
635
735
834
934
1033
1133
1232
1332
1431
1530
1630
1729
1828
1928
2027
2126
2226
2325
2425
2524
2624
2723
2823
2922
3022

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 31% of days. Sticky, muggy-or-worse air turns up on roughly 53% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
10112373218
20213383116
30214393014
41315393013
51316402911
61417402810
7141841288
8152040277
9262140266
10272240255
11282439244
12292538223
133102637213
143112836202
154122935192
165133033172
175153132161
186163131151
197173230131
207193328121
218203427111
229213426101
231022342481
241123342371
251324342171
261425342060
271626341950
281827331840
292027321640
302228321530

Wind in September

Winds average 16 km/h in September.

Across September, daily wind ranges from about 16 km/h on the calmest days to 17 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202530
Wind speed (km/h)Feels
116light breeze
216light breeze
316light breeze
416light breeze
516light breeze
616light breeze
716light breeze
816light breeze
916light breeze
1016light breeze
1116light breeze
1216light breeze
1316light breeze
1416light breeze
1516light breeze
1616light breeze
1717light breeze
1817light breeze
1917light breeze
2017light breeze
2117light breeze
2217light breeze
2317light breeze
2417light breeze
2517light breeze
2617light breeze
2716light breeze
2816light breeze
2916light breeze
3016light breeze

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 6:06 AM to 6:28 AM, and sunset from 6:52 PM to 6:09 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.86:066:52
212.76:076:51
312.76:086:49
412.76:086:48
512.66:096:46
612.66:106:45
712.56:116:43
812.56:116:42
912.56:126:40
1012.46:136:39
1112.46:146:38
1212.46:146:36
1312.36:156:35
1412.36:166:33
1512.36:166:32
1612.26:176:30
1712.26:186:29
1812.16:196:27
1912.16:196:26
2012.16:206:24
2112.06:216:23
2212.06:226:21
2312.06:226:20
2411.96:236:18
2511.96:246:17
2611.86:256:15
2711.86:266:14
2811.86:266:12
2911.76:276:11
3011.76:286:09

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.32 kWh/m².

For context, solar energy here swings from a low near 2.65 kWh/m² to a high of 5.79 kWh/m² in May across the year — September's 4.32 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
14.5Bright
24.5Bright
34.5Bright
44.5Bright
54.4Bright
64.4Bright
74.4Bright
84.4Bright
94.4Bright
104.4Bright
114.4Bright
124.3Bright
134.3Bright
144.3Bright
154.3Bright
164.3Bright
174.3Bright
184.3Bright
194.3Bright
204.3Bright
214.3Bright
224.3Bright
234.3Bright
244.2Bright
254.2Bright
264.2Bright
274.2Bright
284.2Bright
294.2Bright
304.2Bright
Planning a trip in September

Hazard calendar for Yeosu

In seasonPeak

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

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

Yeosu's rainy season runs April–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 Yeosu?

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

7.0
Sightseeing
2nd-best month of the year
6.0
Beach & pool
2nd-best month of the year

September is one of the better times to visit Yeosu for general sightseeing.

What to pack for Yeosu in September

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

In September, Yeosu sees daytime highs around 24°C and nights near 21°C. Worth packing: light clothes and rain gear. About 9 days see rain.

light clothesrain gear

Sea temperature near Yeosu in September

The nearest coast averages about 24°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 15 km away) is warmest in August at about 26°C and coldest in February near 12°C.

It's comfortable for a long swim from Jun 20 to Oct 22 — about 4.1 months when the water holds above 20°C.

10°15°20°25°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan13Bracing
Feb12Bracing
Mar12Bracing
Apr13Bracing
May16Cool
Jun20Cool
Jul23Refreshing
Aug26Warm
Sep24Warm
Oct21Refreshing
Nov17Cool
Dec14Bracing

UV index in Yeosu in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 9 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Yeosu peaks around August 20 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 20UV 9Dec 23UV 2
UV index (midday)Level
Jan2Moderate
Feb4Moderate
Mar6High
Apr7High
May8Very high
Jun8Very high
Jul8Very high
Aug9Very high
Sep9Very high
Oct5High
Nov4Moderate
Dec2Moderate

Air quality in Yeosu 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 Yeosu is worst in March — around 42 µg/m³ PM2.5 (poor), about 2.4× the cleanest month (July, 18 µg/m³).

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

0204060JanFebMarAprMayJunJulAugSepOctNovDecModeratePoorModerateMar 1841 µg/m³Jul 2318 µg/m³
PM2.5 (µg/m³)Level
Jan30Moderate
Feb35Poor
Mar42Poor
Apr37Poor
May31Moderate
Jun25Moderate
Jul18Moderate
Aug18Moderate
Sep22Moderate
Oct24Moderate
Nov27Moderate
Dec26Moderate
Location & terrain

Where is Yeosu?

Yeosu sits at 34.8°N, 127.7°E, 10 m above sea level, in South Korea. The nearest listed city is Gwangyang, 20 km away.

HadongKuryeBoseongChinju

Topography around Yeosu

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

Within 3 km, the terrain around Yeosu has significant variations in elevation — a maximum elevation change of 327 m around an average of 63 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 502 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,875 m.

The land around Yeosu is covered by trees (40%) and artificial surfaces (30%) within 3 km, water (52%) and trees (30%) within 16 km, and water (46%) and trees (44%) within 80 km.

3 km
327 m
16 km
502 m
80 km
1,875 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Gwangyang 20 km · Kwangyang 25 km · Suncheon 26 km · Beolgyo 31 km · Hadong 35 km · Kurye 53 km · Boseong 53 km · Chinju 62 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 Yeosu (34.7606°, 127.6621°, 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).