Sepatan weather in September

In September, Sepatan sees average daytime highs of 32°C and overnight lows near 25°C, with 49 mm of rain across 11.2 wet days and about 12 hours of daylight. It is the 2nd-warmest and 11th-wettest month of the year here.

Day-to-day highs hold fairly steady near 32°C through the month. The sky is clear or mostly clear about 26% of the time in September, and the air most often feels oppressive.

Daylight stretches from about 11 h 54 min at the start of September to 12 hours by month's end. Set against the rest of the year, September is Sepatan's 4th-clearest and 10th-windiest month. For the whole year in context, see Sepatan's year-round climate.

Daytime high
32°
2nd warmest
Overnight low
25°
8th coldest
Rainfall
49 mm
11.2 wet days
Daylight
12 hours
5:49 AM – 5:47 PM
Cloud cover
59%
4th clearest
Wind
7 km/h
10th windiest
Solar energy
6.18 kWh/m²
Travel score
4.0
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 32°C through the month.

A typical September day in Sepatan reaches about 32°C in the afternoon and slips back to 25°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 30°C and 33°C. Set against its neighbours, September runs on par with August and on par with October.

20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
13125
23125
33125
43125
53125
63225
73225
83225
93225
103225
113225
123225
133225
143225
153225
163225
173225
183225
193225
203226
213226
223226
233226
243226
253226
263226
273226
283226
293226
303226

How September really feels in Sepatan

Once humidity and wind are folded in, September averages 30 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
30
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

The story in September is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Sepatan weather by month

How September compares with the rest of the year at a glance. September is the 2nd-warmest and 11th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan30° / 25°27928.512.32.8
Feb30° / 25°25026.412.22.7
Mar31° / 25°23228122.7
Apr31° / 26°19125.711.92.8
May31° / 26°12920.611.73.3
Jun31° / 25°9715.911.73.9
Jul31° / 25°681311.74.3
Aug31° / 25°389.811.84.5
Sep32° / 25°4911.2124.0
Oct32° / 26°10718.412.13.3
Nov31° / 26°18224.612.32.8
Dec30° / 25°24526.112.32.9

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 26% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 24% of September, with mostly cloudy or overcast conditions the remaining 50%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15644
25644
35644
45644
55743
65743
75644
85545
95545
105446
115347
125248
135149
145050
155050
165050
174951
184852
194852
204654
214654
224555
234654
244654
254555
264555
274555
284357
294258
304159

Chance of precipitation in September

Any precipitation

Sepatan gets around 49 mm of rain over 11.2 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 46% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
134
235
335
435
535
635
735
836
936
1036
1136
1236
1336
1436
1536
1636
1736
1837
1937
2037
2138
2238
2339
2440
2541
2642
2743
2844
2945
3046

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the oppressive band about 85% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Muggy (%)Oppressive (%)Miserable (%)
148511
248511
348610
448610
548610
648610
748610
848610
948610
1048610
1148610
1248610
1348610
1448610
1538710
1638611
1738611
1838512
1928612
2028513
2128513
2228414
2318415
2418316
2518316
2618217
2718118
2818019
2908119
3008020

Wind in September

Winds average 7 km/h in September.

Across September, daily wind ranges from about 7 km/h on the calmest days to 7 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (km/h)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 11 h 54 min at the start of September to 12 hours by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 6 minutes over September. Sunrise moves from 5:57 AM to 5:42 AM, and sunset from 5:50 PM to 5:44 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
111.95:575:50
211.95:565:50
311.95:565:50
411.95:555:49
511.95:555:49
611.95:545:49
711.95:545:49
811.95:535:49
911.95:535:48
1011.95:525:48
1111.95:525:48
1211.95:515:48
1311.95:515:48
1412.05:505:47
1512.05:505:47
1612.05:495:47
1712.05:485:47
1812.05:485:47
1912.05:475:46
2012.05:475:46
2112.05:465:46
2212.05:465:46
2312.05:455:46
2412.05:455:45
2512.05:445:45
2612.05:445:45
2712.05:435:45
2812.05:435:45
2912.05:425:45
3012.05:425:44

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 6.18 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 4.8 kWh/m² to a high of 6.18 kWh/m² in September across the year — September's 6.18 kWh/m² sits near the top of that range.

0246151015202530
Solar energy (kWh/m²)Level
16.0Bright
26.0Intense
36.0Intense
46.0Intense
56.1Intense
66.1Intense
76.1Intense
86.1Intense
96.1Intense
106.1Intense
116.2Intense
126.2Intense
136.2Intense
146.2Intense
156.2Intense
166.2Intense
176.2Intense
186.2Intense
196.2Intense
206.2Intense
216.2Intense
226.2Intense
236.2Intense
246.2Intense
256.2Intense
266.2Intense
276.2Intense
286.2Intense
296.2Intense
306.2Intense
Planning a trip in September

Hazard calendar for Sepatan

In seasonPeak

None of Sepatan's seasonal hazards are active in September. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.

Sepatan sits in the South Indian Ocean cyclone belt; the season peaks January–March.

Sepatan's rainy season runs November–May, when most of the year's rain falls.

Cyclone
Rainy season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Sepatan?

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

4.0
Sightseeing
3rd-best month of the year
6.2
Beach & pool
3rd-best month of the year

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

What to pack for Sepatan in September

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

In September, Sepatan sees daytime highs around 32°C and nights near 25°C. Pack light clothes and sun protection. Worth having: rain gear. About 11 days see rain.

light clothessun protectionrain gear

Sea temperature near Sepatan in September

The nearest coast averages about 29°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 28 km away) is warmest in May at about 30°C and coldest in January near 29°C.

The water stays above 20°C all year — warm enough for a swim any month.

28°30°32°JanFebMarAprMayJunJulAugSepOctNovDecwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan29Tropical
Feb29Tropical
Mar29Tropical
Apr30Tropical
May30Tropical
Jun30Tropical
Jul29Tropical
Aug29Tropical
Sep29Tropical
Oct29Tropical
Nov30Tropical
Dec29Tropical

UV index in Sepatan in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 10 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Sepatan peaks around March 15 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near November 16 at about 7 (very high).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highExtremeVery highMar 15UV 15Nov 16UV 7
UV index (midday)Level
Jan13Extreme
Feb13Extreme
Mar15Extreme
Apr12Extreme
May9Very high
Jun8Very high
Jul9Very high
Aug9Very high
Sep10Very high
Oct11Extreme
Nov7High
Dec11Extreme

Air quality in Sepatan 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 Sepatan is worst in May — around 74 µg/m³ PM2.5 (unhealthy), about 1.9× the cleanest month (December, 38 µg/m³).

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

020406080JanFebMarAprMayJunJulAugSepOctNovDecPoorUnhealthyPoorMay 2073 µg/m³Dec 2438 µg/m³
PM2.5 (µg/m³)Level
Jan39Poor
Feb41Poor
Mar51Poor
Apr62Unhealthy
May74Unhealthy
Jun69Unhealthy
Jul67Unhealthy
Aug67Unhealthy
Sep70Unhealthy
Oct69Unhealthy
Nov61Unhealthy
Dec38Poor
Location & terrain

Where is Sepatan?

Sepatan sits at 6.1°S, 106.6°E, 11 m above sea level, in Indonesia. The nearest listed city is Teluknaga, 7.0 km away.

Topography around Sepatan

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

Within 3 km, the terrain around Sepatan has only modest variations in elevation — a maximum elevation change of 15 m around an average of 9 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 46 m; within 80 km, very significant variations in elevation — a maximum elevation change of 2,184 m.

The land around Sepatan is covered by artificial surfaces (42%) and cropland (40%) within 3 km, artificial surfaces (39%) and cropland (21%) within 16 km, and water (42%) and trees (34%) within 80 km.

3 km
15 m
16 km
46 m
80 km
2,184 m
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
September weather nearby: Teluknaga 7.0 km · Pasarkemis 8.0 km · Tangerang 9.0 km · Cikupa 15 km · Curug 16 km · Ciputat 19 km · Kresek 22 km · Serpong 24 km

Indonesia travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type C / F
230 V · 50 Hz
Prices
≈ 29% of US
price level, 2025
GDP per capita
$5,060
2025
Happiness
5.6 / 10
World Happiness, 2025
Safe drinking water
30%
of population, 2024
Homicide rate
0.3
per 100k, 2022
Road deaths
11.3
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Low
EF EPI 471
Religion
Muslim 87%Protestant 8%Roman Catholic 3%Hindu 2%

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 Sepatan (-6.1189°, 106.575°, elevation 11 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).