Cilacap weather in September

In September, Cilacap sees average daytime highs of 26°C and overnight lows near 24°C, with 110 mm of rain across 17.9 wet days and about 12 hours of daylight. It is the 11th-warmest and 10th-wettest month of the year here.

Day-to-day highs hold fairly steady near 26°C through the month. The sky is clear or mostly clear about 29% 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 h 06 min by month's end. Set against the rest of the year, September is Cilacap's 4th-clearest and 2nd-windiest month. For the whole year in context, see Cilacap's year-round climate.

Daytime high
26°
11th warmest
Overnight low
24°
2nd coldest
Rainfall
110 mm
17.9 wet days
Daylight
12 hours
5:40 AM – 5:37 PM
Cloud cover
58%
4th clearest
Wind
17 km/h
2nd windiest
Solar energy
5.61 kWh/m²
Travel score
5.4
out of 10

Cilacap is capital of Cilacap Regency.

Founded
1982

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

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 26°C through the month.

A typical September day in Cilacap reaches about 26°C in the afternoon and slips back to 24°C overnight — a 2°C spread between the day's warmth and the night's chill. On most days the high lands between 25°C and 27°C. Set against its neighbours, September runs on par with August and on par with October.

20°23°25°28°30°151015202530
Avg high (°C)Avg low (°C)
12624
22624
32624
42624
52624
62624
72624
82624
92624
102624
112624
122624
132624
142624
152624
162624
172624
182624
192624
202624
212624
222624
232624
242624
252624
262624
272624
282624
292624
302624

How September really feels in Cilacap

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.

Cilacap weather by month

How September compares with the rest of the year at a glance. September is the 11th-warmest and 10th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan28° / 26°31628.212.43.6
Feb28° / 26°2402512.33.6
Mar28° / 26°25927.912.13.4
Apr28° / 26°2062711.83.4
May28° / 26°1622511.74.0
Jun28° / 25°12721.411.64.8
Jul27° / 25°10117.711.65.5
Aug26° / 24°7215.311.76.0
Sep26° / 24°11017.9125.4
Oct27° / 25°22123.412.24.6
Nov27° / 25°36527.512.43.6
Dec28° / 26°39428.112.43.5

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 29% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 25% of September, with mostly cloudy or overcast conditions the remaining 47%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15941
25941
35941
45941
55941
65941
75941
85941
95842
105842
115743
125743
135545
145446
155347
165248
175248
185248
195149
205050
214951
224951
234852
244951
254852
264852
274753
284654
294654
304555

Chance of precipitation in September

Any precipitation

Cilacap gets around 110 mm of rain over 17.9 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 60% and peaks near 64% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
153
254
355
455
556
657
757
858
958
1059
1159
1260
1360
1461
1561
1662
1762
1862
1962
2062
2162
2262
2362
2462
2562
2662
2763
2863
2963
3064

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 89% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Muggy (%)Oppressive (%)Miserable (%)
117821
216831
316831
415841
515841
614860
714860
814860
913870
1013870
1113870
1212880
1312871
1411881
1511881
1611881
1710891
1810891
199901
209901
218911
227921
237921
246931
256931
266922
275932
285932
295932
304933

Wind in September

Winds average 17 km/h in September.

Across September, daily wind ranges from about 15 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
117light breeze
217light breeze
317light breeze
417light breeze
517light breeze
617light breeze
717light breeze
817light breeze
917light breeze
1017light breeze
1117light breeze
1217light breeze
1317light breeze
1417light breeze
1517light breeze
1617light breeze
1717light breeze
1817light breeze
1916light breeze
2016light breeze
2116light breeze
2216light breeze
2316light breeze
2416light breeze
2516light breeze
2616light breeze
2716light breeze
2816light breeze
2916light breeze
3015light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 11 h 54 min at the start of September to 12 h 06 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 12 minutes over September. Sunrise moves from 5:48 AM to 5:31 AM, and sunset from 5:39 PM to 5:35 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
111.95:485:39
211.95:485:39
311.95:475:39
411.95:475:39
511.95:465:39
611.95:455:39
711.95:455:38
811.95:445:38
911.95:445:38
1011.95:435:38
1111.95:425:38
1211.95:425:38
1311.95:415:37
1411.95:415:37
1512.05:405:37
1612.05:405:37
1712.05:395:37
1812.05:385:37
1912.05:385:37
2012.05:375:36
2112.05:375:36
2212.05:365:36
2312.05:355:36
2412.05:355:36
2512.05:345:36
2612.05:345:36
2712.05:335:35
2812.05:335:35
2912.15:325:35
3012.15:315:35

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.61 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 4.58 kWh/m² to a high of 5.61 kWh/m² in September across the year — September's 5.61 kWh/m² sits near the top of that range.

0246151015202530
Solar energy (kWh/m²)Level
15.5Bright
25.5Bright
35.5Bright
45.5Bright
55.5Bright
65.5Bright
75.5Bright
85.6Bright
95.6Bright
105.6Bright
115.6Bright
125.6Bright
135.6Bright
145.6Bright
155.6Bright
165.6Bright
175.6Bright
185.6Bright
195.6Bright
205.6Bright
215.6Bright
225.6Bright
235.6Bright
245.6Bright
255.6Bright
265.6Bright
275.6Bright
285.6Bright
295.6Bright
305.6Bright
Planning a trip in September

Hazard calendar for Cilacap

In seasonPeak

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

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

Cilacap's rainy season runs October–April, 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 Cilacap?

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

5.4
Sightseeing
3rd-best month of the year
5.2
Beach & pool
3rd-best month of the year

September is a reasonable time to visit Cilacap for sightseeing.

What to pack for Cilacap in September

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

In September, Cilacap sees daytime highs around 26°C and nights near 24°C. Pack rain gear. Worth having: light clothes and sun protection. About 18 days see rain.

rain gearlight clothessun protection

Sea temperature near Cilacap in September

The nearest coast averages about 26°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 21 km away) is warmest in April at about 29°C and coldest in August near 26°C.

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

24°26°28°30°JanFebMarAprMayJunJulAugSepOctNovDecwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan29Tropical
Feb29Tropical
Mar29Tropical
Apr29Tropical
May29Tropical
Jun28Warm
Jul27Warm
Aug26Warm
Sep26Warm
Oct27Warm
Nov28Warm
Dec29Tropical

UV index in Cilacap in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 12 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Cilacap peaks around March 12 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 14 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 highExtremeExtremeMar 12UV 15Jun 14UV 7
UV index (midday)Level
Jan14Extreme
Feb14Extreme
Mar15Extreme
Apr12Extreme
May9Very high
Jun7High
Jul10Very high
Aug11Extreme
Sep12Extreme
Oct13Extreme
Nov9Very high
Dec12Extreme

Air quality in Cilacap 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 Cilacap is worst in May — around 46 µg/m³ PM2.5 (poor), and holds fairly steady the rest of the year.

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

0204060JanFebMarAprMayJunJulAugSepOctNovDecPoorModerateMay 1545 µg/m³Sep 1630 µg/m³
PM2.5 (µg/m³)Level
Jan39Poor
Feb39Poor
Mar41Poor
Apr44Poor
May46Poor
Jun43Poor
Jul37Poor
Aug31Moderate
Sep30Moderate
Oct31Moderate
Nov32Moderate
Dec33Moderate
Location & terrain

Where is Cilacap?

Cilacap sits at 7.7°S, 109.0°E, 10 m above sea level, in Indonesia. The nearest listed city is Wangon, 24 km away.

Topography around Cilacap

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

Within 3 km, the terrain around Cilacap has only modest variations in elevation — a maximum elevation change of 123 m around an average of 6 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 209 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,396 m.

The land around Cilacap is covered by artificial surfaces (42%) and water (36%) within 3 km, water (51%) and trees (24%) within 16 km, and trees (49%) and water (35%) within 80 km.

3 km
123 m
16 km
209 m
80 km
3,396 m
treesgrasslandcroplandartificial surfaceswatermangroves
September weather nearby: Wangon 24 km · Kroya 28 km · Sidareja 36 km · Banyumas 39 km · Purwokerto 42 km · Sokaraja 43 km · Baturaden 53 km · Purbalingga 54 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 Cilacap (-7.7264°, 109.0094°, 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).