Siheungdong weather in September

In September, Siheungdong sees average daytime highs of 26°C and overnight lows near 17°C, with 124 mm of rain across 7.6 wet days and about 12.3 hours of daylight. It is the 4th-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 36% of the time in September, and the air most often feels humid.

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 Siheungdong's 9th-clearest and 12th-windiest month. For the whole year in context, see Siheungdong's year-round climate.

Daytime high
26°
4th warmest
Overnight low
17°
9th coldest
Rainfall
124 mm
7.6 wet days
Daylight
12 h 12 min
6:20 AM – 6:34 PM
Cloud cover
56%
9th clearest
Wind
8 km/h
12th windiest
Solar energy
4.22 kWh/m²
Travel score
7.1
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 Siheungdong reaches about 26°C in the afternoon and slips back to 17°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 22°C and 29°C. Set against its neighbours, September runs about 4°C cooler than August and about 6°C warmer than October.

10°20°30°151015202530
Avg high (°C)Avg low (°C)
12820
22720
32719
42719
52719
62719
72719
82718
92718
102618
112618
122618
132617
142617
152617
162617
172516
182516
192516
202516
212515
222515
232415
242415
252414
262414
272414
282314
292313
302313

How September really feels in Siheungdong

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.

Siheungdong weather by month

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

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / -7°203.62.29.70.0
Feb / -5°2541.810.60.3
Mar11° / 386.2111.72.9
Apr18° / 707.3012.96.0
May23° / 12°967.70147.2
Jun27° / 18°1268.8014.56.6
Jul28° / 22°31416.5014.34.8
Aug29° / 22°25815.2013.44.8
Sep26° / 17°1247.6012.37.1
Oct20° / 555.30117.1
Nov12° / 477.10.4103.3
Dec / -5°234.81.59.50.1

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 36% 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 49%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14654
24654
34753
44753
54753
64951
74951
84852
94951
104951
114951
124951
135050
145149
155149
165149
175347
185347
195347
205347
215446
225446
235446
245446
255446
265545
275644
285644
295644
305743

Chance of precipitation in September

Any precipitation

Siheungdong gets around 124 mm of rain over 7.6 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 27% and peaks near 38% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%50%151015202530
Rain chance (%)
138
237
335
434
533
632
731
830
929
1028
1128
1227
1327
1426
1526
1626
1725
1824
1924
2023
2123
2223
2322
2422
2522
2621
2721
2820
2920
3019

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 31% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1172439263
2282538252
3292638232
42102737212
53112837191
64132936181
75142936161
85153035141
97173034130
108183033110
119203031100
121121303080
131222302870
141424292760
151625292550
161827282350
172028282140
182129271930
192330261730
202532261520
212733251420
222933241210
233134231010
24333522910
25353521810
26373520610
27403519500
28423518500
29453417400
30473416400

Wind in September

Winds average 8 km/h in September, the calmest month.

Across September, daily wind ranges from about 8 km/h on the calmest days to 8 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (km/h)Feels
18calm
28calm
38calm
48calm
58calm
68calm
78calm
88calm
98calm
108calm
118calm
128calm
138calm
148calm
158calm
168calm
178calm
188calm
198calm
208calm
218calm
228calm
238calm
248calm
258calm
268calm
278calm
288calm
298calm
308calm

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 6:07 AM to 6:32 AM, and sunset from 6:57 PM to 6:11 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.86:076:57
212.86:086:56
312.86:086:54
412.76:096:53
512.76:106:51
612.66:116:50
712.66:126:48
812.66:136:47
912.56:146:45
1012.56:146:43
1112.46:156:42
1212.46:166:40
1312.46:176:39
1412.36:186:37
1512.36:196:35
1612.26:206:34
1712.26:206:32
1812.26:216:31
1912.16:226:29
2012.16:236:27
2112.06:246:26
2212.06:256:24
2311.96:266:23
2411.96:276:21
2511.96:276:19
2611.86:286:18
2711.86:296:16
2811.76:306:15
2911.76:316:13
3011.76:326:11

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.22 kWh/m².

For context, solar energy here swings from a low near 2.35 kWh/m² to a high of 5.79 kWh/m² in May across the year — September's 4.22 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
14.3Bright
24.3Bright
34.3Bright
44.3Bright
54.3Bright
64.3Bright
74.3Bright
84.3Bright
94.3Bright
104.3Bright
114.2Bright
124.2Bright
134.2Bright
144.2Bright
154.2Bright
164.2Bright
174.2Bright
184.2Bright
194.2Bright
204.2Bright
214.2Bright
224.2Bright
234.1Bright
244.1Bright
254.1Bright
264.1Bright
274.1Bright
284.1Bright
294.0Bright
304.0Bright
Planning a trip in September

Hazard calendar for Siheungdong

In seasonPeak

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

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

Siheungdong'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 Siheungdong?

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

7.1
Sightseeing
2nd-best month of the year
6.5
Beach & pool
2nd-best month of the year

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

What to pack for Siheungdong in September

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

In September, Siheungdong sees daytime highs around 26°C and nights near 17°C. Worth packing: light clothes. About 8 days see rain.

light clothes

Sea temperature near Siheungdong 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 27 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 11 to Oct 13 — about 3.1 months when the water holds above 20°C.

0°10°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan6Bracing
Feb4Bracing
Mar5Bracing
Apr8Bracing
May12Bracing
Jun17Cool
Jul21Refreshing
Aug24Refreshing
Sep23Refreshing
Oct20Cool
Nov15Bracing
Dec10Bracing

UV index in Siheungdong 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 Siheungdong peaks around July 22 at about 8 (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 8Dec 23UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar4Moderate
Apr6High
May5High
Jun7High
Jul8Very high
Aug8Very high
Sep7High
Oct5Moderate
Nov3Moderate
Dec2Low

Air quality in Siheungdong 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 Siheungdong 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 Siheungdong?

Siheungdong sits at 37.5°N, 126.9°E, 35 m above sea level, in South Korea. The nearest listed city is Gwangmyeong, 5.0 km away.

Topography around Siheungdong

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

Within 3 km, the terrain around Siheungdong has significant variations in elevation — a maximum elevation change of 460 m around an average of 99 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 604 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,443 m.

The land around Siheungdong is covered by trees (49%) and artificial surfaces (48%) within 3 km, artificial surfaces (46%) and trees (43%) within 16 km, and trees (44%) and water (22%) within 80 km.

3 km
460 m
16 km
604 m
80 km
1,443 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Gwangmyeong 5.0 km · Anyang-si 7.0 km · Gunpo 10 km · Uiwang 10 km · Bucheon-si 12 km · Seoul 14 km · Ansan 16 km · Incheon 18 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 Siheungdong (37.4518°, 126.9108°, elevation 35 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).