Ganghwa-gun weather in September

In September, Ganghwa-gun sees average daytime highs of 25°C and overnight lows near 18°C, with 116 mm of rain across 6.9 wet days and about 12.3 hours of daylight. It is the 3rd-warmest and 4th-wettest month of the year here.

Highs ease over the month, from about 27°C in the first days to 23°C by the end. The sky is clear or mostly clear about 40% of the time in September, and the air most often feels humid.

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 Ganghwa-gun's 9th-clearest and 11th-windiest month. For the whole year in context, see Ganghwa-gun's year-round climate.

Daytime high
25°
3rd warmest
Overnight low
18°
9th coldest
Rainfall
116 mm
6.9 wet days
Daylight
12 h 12 min
6:21 AM – 6:36 PM
Cloud cover
54%
9th clearest
Wind
9 km/h
11th windiest
Solar energy
4.36 kWh/m²
Travel score
7.2
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 27°C in the first days to 23°C by the end.

A typical September day in Ganghwa-gun reaches about 25°C in the afternoon and slips back to 18°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 22°C and 28°C. Set against its neighbours, September runs about 3°C cooler than August and about 6°C warmer than October.

10°15°20°25°30°151015202530
Avg high (°C)Avg low (°C)
12721
22720
32720
42720
52720
62720
72620
82619
92619
102619
112619
122619
132618
142618
152518
162518
172517
182517
192517
202517
212417
222416
232416
242416
252416
262415
272315
282315
292315
302314

How September really feels in Ganghwa-gun

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.

Ganghwa-gun 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 / -6°173.52.19.70.0
Feb / -4°233.81.510.50.1
Mar / 335.20.711.72.3
Apr16° / 637012.95.3
May21° / 13°967.70146.9
Jun25° / 18°1208.7014.66.9
Jul27° / 22°30315.3014.35.4
Aug29° / 23°25114.2013.55.2
Sep25° / 18°1166.9012.37.2
Oct19° / 11°525.10117.0
Nov11° / 477.10.4103.1
Dec / -3°224.71.19.40.1

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 40% 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 46%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14951
24951
34951
45149
55149
65149
75248
85248
95149
105248
115248
125347
135347
145446
155446
165545
175545
185644
195644
205743
215743
225743
235743
245743
255743
265743
275743
285743
295842
305842

Chance of precipitation in September

Any precipitation

Ganghwa-gun gets around 116 mm of rain over 6.9 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 24% and peaks near 37% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%50%151015202530
Rain chance (%)
137
236
335
434
533
632
730
829
928
1027
1127
1226
1325
1424
1523
1622
1721
1820
1920
2019
2118
2218
2318
2418
2517
2617
2717
2817
2917
3017

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the humid band about 26% of days. Sticky, muggy-or-worse air turns up on roughly 33% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1182238283
2192438262
32102537242
42112637231
53122737211
63132737191
74142836171
85162836150
96172935140
107182934120
118202933100
12921293190
131123293080
141224292870
151426292660
161527282450
171729282240
181830282140
192031281930
202132271720
212333271520
222534261320
232735261210
242935251010
25313624910
26333623810
27353622700
28383620600
29413519500
30433418500

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 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
79calm
89calm
99calm
109calm
119calm
129calm
139calm
149calm
159calm
169calm
179calm
189calm
199calm
2010calm
2110calm
2210calm
2310calm
2410calm
2510calm
2610calm
2710calm
2810calm
2910calm
3010calm

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 6:08 AM to 6:34 AM, and sunset from 6:59 PM to 6:13 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.96:086:59
212.86:096:58
312.86:106:56
412.76:116:55
512.76:126:53
612.76:136:52
712.66:136:50
812.66:146:48
912.56:156:47
1012.56:166:45
1112.46:176:44
1212.46:186:42
1312.46:196:40
1412.36:196:39
1512.36:206:37
1612.26:216:36
1712.26:226:34
1812.26:236:32
1912.16:246:31
2012.16:256:29
2112.06:266:27
2212.06:266:26
2311.96:276:24
2411.96:286:23
2511.96:296:21
2611.86:306:19
2711.86:316:18
2811.76:326:16
2911.76:336:15
3011.76:346:13

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.36 kWh/m².

For context, solar energy here swings from a low near 2.31 kWh/m² to a high of 5.82 kWh/m² in May across the year — September's 4.36 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
14.4Bright
24.4Bright
34.4Bright
44.4Bright
54.4Bright
64.4Bright
74.4Bright
84.4Bright
94.4Bright
104.4Bright
114.4Bright
124.4Bright
134.4Bright
144.4Bright
154.4Bright
164.4Bright
174.3Bright
184.3Bright
194.3Bright
204.3Bright
214.3Bright
224.3Bright
234.3Bright
244.2Bright
254.2Bright
264.2Bright
274.2Bright
284.1Bright
294.1Bright
304.1Bright
Planning a trip in September

Hazard calendar for Ganghwa-gun

In seasonPeak

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

Ganghwa-gun sits in the Pacific typhoon belt; the season peaks July–October.

Ganghwa-gun's rainy season runs July–August, 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 Ganghwa-gun?

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

7.2
Sightseeing
1st-best month of the year
6.5
Beach & pool
1st-best month of the year

September is one of the better times to visit Ganghwa-gun for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Ganghwa-gun in September

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

In September, Ganghwa-gun sees daytime highs around 25°C and nights near 18°C. Worth packing: light clothes. About 7 days see rain.

light clothes

Sea temperature near Ganghwa-gun 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 17 km away) is warmest in August at about 24°C and coldest in February near 4°C.

It's comfortable for a long swim from Jul 7 to Oct 10 — about 3.2 months when the water holds above 20°C.

0°10°20°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan5Bracing
Feb4Bracing
Mar5Bracing
Apr8Bracing
May13Bracing
Jun17Cool
Jul21Refreshing
Aug24Warm
Sep23Refreshing
Oct19Cool
Nov14Bracing
Dec9Bracing

UV index in Ganghwa-gun in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September 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 Ganghwa-gun peaks around July 22 at about 7 (very high) — sunscreen and a hat are worth it in the middle of the day. 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 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateJul 22UV 7Dec 23UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar4Moderate
Apr6High
May6High
Jun7High
Jul8Very high
Aug7Very high
Sep7High
Oct5Moderate
Nov3Moderate
Dec2Low

Air quality in Ganghwa-gun 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 Ganghwa-gun is worst in March — around 160 µg/m³ PM2.5 (very unhealthy), about 2.0× the cleanest month (August, 81 µg/m³).

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

0306090120150180JanFebMarAprMayJunJulAugSepOctNovDecUnhealthyVery unhealthyUnhealthyMar 13158 µg/m³Aug 1282 µg/m³
PM2.5 (µg/m³)Level
Jan145Unhealthy
Feb149Unhealthy
Mar160Very unhealthy
Apr127Unhealthy
May111Unhealthy
Jun98Unhealthy
Jul88Unhealthy
Aug81Unhealthy
Sep110Unhealthy
Oct132Unhealthy
Nov142Unhealthy
Dec133Unhealthy
Location & terrain

Where is Ganghwa-gun?

Ganghwa-gun sits at 37.7°N, 126.5°E, 15 m above sea level, in South Korea. The nearest listed city is Gimpo-si, 24 km away.

Yŏnan-ŭpIncheonBucheon-si

Topography around Ganghwa-gun

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

Within 3 km, the terrain around Ganghwa-gun has only modest variations in elevation — a maximum elevation change of 227 m around an average of 38 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 449 m; within 80 km, large variations in elevation — a maximum elevation change of 924 m.

The land around Ganghwa-gun is covered by trees (39%) and cropland (30%) within 3 km, cropland (31%), trees (30%) and water (23%) within 16 km, and water (33%) and trees (31%) within 80 km.

3 km
227 m
16 km
449 m
80 km
924 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Gimpo-si 24 km · Kaesŏng 26 km · Munsan 29 km · Paech’ŏn-ŭp 32 km · Goyang-si 32 km · Yŏnan-ŭp 34 km · Incheon 38 km · Bucheon-si 38 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 Ganghwa-gun (37.7472°, 126.4856°, elevation 15 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).