Cepu weather in September

In September, Cepu sees average daytime highs of 34°C and overnight lows near 23°C, with 30 mm of rain across 4.5 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 34°C through the month. The sky is clear or mostly clear about 32% of the time in September, and the air most often feels muggy.

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 Cepu's 3rd-clearest and 3rd-windiest month. For the whole year in context, see Cepu's year-round climate.

Daytime high
34°
2nd warmest
Overnight low
23°
3rd coldest
Rainfall
30 mm
4.5 wet days
Daylight
12 hours
5:29 AM – 5:27 PM
Cloud cover
56%
3rd clearest
Wind
7 km/h
3rd windiest
Solar energy
6.48 kWh/m²
Travel score
3.5
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 34°C through the month.

A typical September day in Cepu reaches about 34°C in the afternoon and slips back to 23°C overnight — a 11°C spread between the day's warmth and the night's chill. On most days the high lands between 32°C and 35°C. Set against its neighbours, September runs about 1°C warmer than August and on par with October.

20°25°30°35°40°151015202530
Avg high (°C)Avg low (°C)
13323
23323
33323
43323
53323
63423
73423
83423
93423
103423
113423
123423
133423
143423
153423
163423
173423
183423
193423
203423
213423
223423
233423
243423
253423
263423
273423
283423
293423
303423

How September really feels in Cepu

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.

Cepu 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
Jan31° / 24°32028.712.42.4
Feb31° / 24°31726.912.22.3
Mar32° / 24°31728.6122.3
Apr32° / 24°23324.911.82.6
May32° / 24°10815.711.73.5
Jun32° / 23°609.611.63.9
Jul32° / 23°315.111.64.2
Aug33° / 22°132.611.84.2
Sep34° / 23°304.5123.5
Oct34° / 24°11812.112.22.8
Nov33° / 24°26823.112.32.3
Dec32° / 24°33227.712.42.3

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 32% 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 44%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15941
26040
36040
46040
55941
65941
75941
85941
95941
105941
115941
125941
135842
145842
155743
165644
175743
185644
195545
205545
215446
225347
235248
245248
255149
265050
274951
284852
294852
304753

Chance of precipitation in September

Any precipitation

Cepu gets around 30 mm of rain over 4.5 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 15% and peaks near 24% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%151015202530
Rain chance (%)
112
212
312
412
512
612
712
812
912
1012
1112
1212
1313
1413
1513
1614
1714
1815
1916
2016
2117
2218
2319
2419
2520
2621
2721
2822
2923
3024

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the muggy band about 63% of days. Sticky, muggy-or-worse air turns up on roughly 87% of them.

0%25%50%75%100%151015202530
Humid (%)Muggy (%)Oppressive (%)Miserable (%)
11466200
21466200
31565200
41565200
51566190
61566190
71665190
81665190
91665190
101664191
111565191
121565191
131565191
141465192
151464202
161463203
171364203
181264204
191165204
201164214
211064215
22964225
23964225
24962236
25862246
26861256
27860266
28859276
29759286
30757306

Wind in September

Winds average 7 km/h in September.

Across September, daily wind ranges from about 6 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
266calm
276calm
286calm
296calm
306calm

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 5:37 AM to 5:21 AM, and sunset from 5:29 PM to 5:25 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
111.95:375:29
211.95:375:29
311.95:365:29
411.95:365:29
511.95:355:29
611.95:355:28
711.95:345:28
811.95:345:28
911.95:335:28
1011.95:335:28
1111.95:325:28
1211.95:315:27
1311.95:315:27
1411.95:305:27
1512.05:305:27
1612.05:295:27
1712.05:295:27
1812.05:285:26
1912.05:275:26
2012.05:275:26
2112.05:265:26
2212.05:265:26
2312.05:255:26
2412.05:255:25
2512.05:245:25
2612.05:235:25
2712.05:235:25
2812.05:225:25
2912.05:225:25
3012.15:215:25

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 6.48 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 4.84 kWh/m² to a high of 6.48 kWh/m² in September across the year — September's 6.48 kWh/m² sits near the top of that range.

0246151015202530
Solar energy (kWh/m²)Level
16.3Intense
26.3Intense
36.3Intense
46.3Intense
56.3Intense
66.4Intense
76.4Intense
86.4Intense
96.4Intense
106.4Intense
116.5Intense
126.5Intense
136.5Intense
146.5Intense
156.5Intense
166.5Intense
176.5Intense
186.5Intense
196.5Intense
206.5Intense
216.5Intense
226.5Intense
236.5Intense
246.5Intense
256.5Intense
266.5Intense
276.5Intense
286.5Intense
296.5Intense
306.5Intense
Planning a trip in September

Hazard calendar for Cepu

In seasonPeak

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

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

Cepu's rainy season runs November–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 Cepu?

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

3.5
Sightseeing
4th-best month of the year
6.8
Beach & pool
3rd-best month of the year

September is a weaker month for outdoor sightseeing in Cepu. The water and warmth also suit a beach or pool day.

What to pack for Cepu in September

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

In September, Cepu sees daytime highs around 34°C and nights near 23°C. Pack light clothes and sun protection. About 5 days see rain.

light clothessun protection

Sea temperature near Cepu 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 58 km away) is warmest in November at about 30°C and coldest in August near 28°C.

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

26°28°30°32°JanFebMarAprMayJunJulAugSepOctNovDecwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan29Tropical
Feb29Tropical
Mar29Tropical
Apr30Tropical
May30Tropical
Jun29Tropical
Jul29Tropical
Aug28Tropical
Sep29Tropical
Oct29Tropical
Nov30Tropical
Dec30Tropical

UV index in Cepu 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 Cepu peaks around March 17 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 15 at about 8 (very high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highExtremeVery highMar 17UV 13Jun 15UV 8
UV index (midday)Level
Jan12Extreme
Feb10Extreme
Mar13Extreme
Apr11Extreme
May9Very high
Jun7Very high
Jul9Very high
Aug11Extreme
Sep12Extreme
Oct12Extreme
Nov9Very high
Dec10Very high

Air quality in Cepu 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 Cepu is worst in May — around 64 µg/m³ PM2.5 (unhealthy), and holds fairly steady the rest of the year.

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

020406080JanFebMarAprMayJunJulAugSepOctNovDecPoorUnhealthyPoorMay 1764 µg/m³Dec 2343 µg/m³
PM2.5 (µg/m³)Level
Jan44Poor
Feb45Poor
Mar53Poor
Apr59Unhealthy
May64Unhealthy
Jun60Unhealthy
Jul54Poor
Aug48Poor
Sep47Poor
Oct49Poor
Nov48Poor
Dec43Poor
Location & terrain

Where is Cepu?

Cepu sits at 7.1°S, 111.6°E, 36 m above sea level, in Indonesia. The nearest listed city is Blora, 27 km away.

Topography around Cepu

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

Within 3 km, the terrain around Cepu has only modest variations in elevation — a maximum elevation change of 65 m around an average of 36 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 267 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,224 m.

The land around Cepu is covered by cropland (33%), trees (31%) and artificial surfaces (24%) within 3 km, trees (46%) and cropland (37%) within 16 km, and trees (42%) and cropland (34%) within 80 km.

3 km
65 m
16 km
267 m
80 km
3,224 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Blora 27 km · Bojonegoro 32 km · Ngawi 33 km · Lasem 53 km · Madiun 54 km · Rembangan 56 km · Tuban 59 km · Nganjuk 61 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 Cepu (-7.1475°, 111.5906°, elevation 36 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).