Jumunjin weather in September

In September, Jumunjin sees average daytime highs of 23°C and overnight lows near 16°C, with 166 mm of rain across 11.1 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 3rd-wettest month of the year here.

Highs ease over the month, from about 24°C in the first days to 21°C by the end. The sky is clear or mostly clear about 30% of the time in September, and the air most often feels comfortable.

Daylight stretches from about 12 h 54 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is Jumunjin's 9th-clearest and 10th-windiest month. For the whole year in context, see Jumunjin's year-round climate.

Daytime high
23°
4th warmest
Overnight low
16°
9th coldest
Rainfall
166 mm
11.1 wet days
Daylight
12 h 12 min
6:12 AM – 6:26 PM
Cloud cover
61%
9th clearest
Wind
9 km/h
10th windiest
Solar energy
4.12 kWh/m²
Travel score
6.5
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 24°C in the first days to 21°C by the end.

A typical September day in Jumunjin reaches about 23°C in the afternoon and slips back to 16°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 19°C and 26°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°151015202530
Avg high (°C)Avg low (°C)
12519
22419
32419
42419
52418
62418
72418
82418
92318
102318
112317
122317
132317
142317
152317
162216
172216
182216
192216
202216
212215
222215
232115
242115
252115
262114
272114
282114
292114
302114

How September really feels in Jumunjin

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.

Jumunjin weather by month

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

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / -5°4465.19.70.0
Feb / -4°425.64.710.50.1
Mar / 598.14.411.72.0
Apr15° / 707.70.9134.9
May20° / 12°787.70146.7
Jun23° / 17°989.7014.66.7
Jul26° / 21°20014.2014.45.9
Aug26° / 21°20515.6013.55.7
Sep23° / 16°16611.1012.36.5
Oct18° / 10°767.80116.2
Nov11° / 637.71.4103.2
Dec / -2°375.22.99.40.2

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 30% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 14% of September, with mostly cloudy or overcast conditions the remaining 55%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
13862
23961
33961
43961
53961
63961
73961
84159
94159
104159
114159
124258
134258
144357
154456
164555
174654
184753
194753
204852
214852
224951
234951
244951
255050
264951
275050
285050
295149
305050

Chance of precipitation in September

Any precipitation

Jumunjin gets around 166 mm of rain over 11.1 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 38% and peaks near 49% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
149
248
347
446
545
645
744
843
942
1042
1141
1240
1340
1439
1538
1637
1736
1835
1935
2034
2133
2232
2332
2431
2531
2630
2730
2830
2929
3029

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the comfortable band about 30% of days. Sticky, muggy-or-worse air turns up on roughly 18% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1114383313
2116393212
3217403011
421841299
532041288
642141277
742341266
852441245
962641234
1082740223
1192940202
12113038192
13133237171
14153336161
15173434151
16193532130
17213630120
18243729100
1926382790
2029382680
2131382460
2234382250
2336382150
2439381940
2542371830
2645361730
2747351520
2850341420
2952331320
3055321210

Wind in September

Winds average 9 km/h in September.

Across September, daily wind ranges from about 9 km/h on the calmest days to 9 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
19calm
29calm
39calm
49calm
59calm
69calm
79calm
89calm
99calm
109calm
119calm
129calm
139calm
149calm
159calm
169calm
179calm
189calm
199calm
209calm
219calm
229calm
239calm
249calm
259calm
269calm
279calm
289calm
299calm
309calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 54 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 72 minutes over September. Sunrise moves from 5:59 AM to 6:24 AM, and sunset from 6:50 PM to 6:04 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.95:596:50
212.86:006:49
312.86:006:47
412.76:016:45
512.76:026:44
612.76:036:42
712.66:046:41
812.66:056:39
912.56:066:38
1012.56:076:36
1112.46:076:34
1212.46:086:33
1312.46:096:31
1412.36:106:29
1512.36:116:28
1612.26:126:26
1712.26:136:25
1812.26:146:23
1912.16:146:21
2012.16:156:20
2112.06:166:18
2212.06:176:16
2311.96:186:15
2411.96:196:13
2511.96:206:12
2611.86:216:10
2711.86:226:08
2811.76:236:07
2911.76:236:05
3011.76:246:04

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.12 kWh/m².

For context, solar energy here swings from a low near 2.38 kWh/m² to a high of 5.9 kWh/m² in May across the year — September's 4.12 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
14.2Bright
24.2Bright
34.2Bright
44.2Bright
54.2Bright
64.2Bright
74.2Bright
84.2Bright
94.2Bright
104.2Bright
114.1Bright
124.1Bright
134.1Bright
144.1Bright
154.1Bright
164.1Bright
174.1Bright
184.1Bright
194.1Bright
204.0Bright
214.0Bright
224.0Bright
234.0Bright
244.0Bright
254.0Bright
264.0Moderate
274.0Moderate
284.0Moderate
293.9Moderate
303.9Moderate
Planning a trip in September

Hazard calendar for Jumunjin

In seasonPeak

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

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

Jumunjin'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 Jumunjin?

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

6.5
Sightseeing
3rd-best month of the year
4.7
Beach & pool
4th-best month of the year

September is a reasonable time to visit Jumunjin for sightseeing.

What to pack for Jumunjin in September

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

In September, Jumunjin sees daytime highs around 23°C and nights near 16°C. Worth packing: light clothes and rain gear. About 11 days see rain.

light clothesrain gear

Sea temperature near Jumunjin in September

The nearest coast averages about 22°C in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea offshore is warmest in August at about 24°C and coldest in February near 9°C.

It's comfortable for a long swim from Jul 1 to Oct 7 — about 3.3 months when the water holds above 20°C.

5°10°15°20°25°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°C)Comfort
Jan10Bracing
Feb9Bracing
Mar9Bracing
Apr12Bracing
May14Bracing
Jun18Cool
Jul22Refreshing
Aug24Warm
Sep22Refreshing
Oct19Cool
Nov16Cool
Dec13Bracing

UV index in Jumunjin 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 Jumunjin peaks around August 16 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 9 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highModerateLowAug 16UV 9Dec 21UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar4Moderate
Apr6High
May6High
Jun8Very high
Jul8Very high
Aug9Very high
Sep8Very high
Oct5High
Nov3Moderate
Dec2Low

Air quality in Jumunjin 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 Jumunjin is worst in March — around 36 µg/m³ PM2.5 (poor), about 2.8× the cleanest month (September, 13 µg/m³).

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

010203040JanFebMarAprMayJunJulAugSepOctNovDecModerateModerateMar 2136 µg/m³Sep 1513 µg/m³
PM2.5 (µg/m³)Level
Jan23Moderate
Feb28Moderate
Mar36Poor
Apr34Moderate
May29Moderate
Jun21Moderate
Jul18Moderate
Aug16Moderate
Sep13Moderate
Oct17Moderate
Nov21Moderate
Dec19Moderate
Location & terrain

Where is Jumunjin?

Jumunjin sits at 37.9°N, 128.8°E, 9 m above sea level, in South Korea. The nearest listed city is Gangneung, 16 km away.

SokchoDonghae CitySantyokuKosongPyeongchangYangguT’aebaek

Topography around Jumunjin

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

Within 3 km, the terrain around Jumunjin has only modest variations in elevation — a maximum elevation change of 96 m around an average of 12 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 1,006 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,646 m.

The land around Jumunjin is covered by water (43%) and trees (30%) within 3 km, water (49%) and trees (43%) within 16 km, and trees (64%) and water (31%) within 80 km.

3 km
96 m
16 km
1,006 m
80 km
1,646 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Gangneung 16 km · Sokcho 41 km · Donghae City 46 km · Santyoku 59 km · Kosong 63 km · Pyeongchang 69 km · Yanggu 77 km · T’aebaek 81 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 Jumunjin (37.8914°, 128.8258°, elevation 9 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).