Cilegon climate

Name: Cilegon
Address: ID

Cilegon is warmest in October, with average highs of 30 °C, and coldest in July, when nights average 24 °C. December is the wettest month (291 mm) and August the driest (69 mm). Figures are 1991–2020 climate normals.

Across a full year Cilegon averages 2,154 mm of rain and 365 days above 25 °C.

Indonesia · population 470,378 · 1991–2020 normals

Temperature below 0 °C to above 30 °C Rain band height is that month’s share of the wettest month

Warmest month October 30 °C
Coldest month July 24 °C
Driest month August 69 mm
Wettest month December 291 mm
Least cloud August 60 % cloud
Hottest on record October 36 °C
Coldest on record September 21 °C
Warmest sea May 30 °C

What to expectCilegon through the year

Cilegon changes little through the year. Average daily highs stay between 29 and 30 °C, so no month stands out as a season in the way it would further from the equator.

Counted across a normal year, 365 days a year reach 25 °C, 77 of them reach 30 °C. The warmest reading in the 1991–2020 record is 36 °C, in October.

Rain is strongly seasonal. December averages 291 mm against 69 mm in August — 4.2 times as much. Planning around the dry months matters more here than planning around temperature.

The sea off Cilegon is warmest in May at 30 °C and coldest in January at 29 °C. Sea temperature lags the air by a month or two, which is why late summer swims warmer than early summer at the same air temperature.

Month by month

Month	Avg high	Rainfall	Cloud
January	28.4 °C	290 mm	89 %
February	28.6 °C	269 mm	90 %
March	28.9 °C	241 mm	86 %
April	29.2 °C	209 mm	81 %
May	29.4 °C	159 mm	69 %
June	29.2 °C	119 mm	62 %
July	29.2 °C	92 mm	61 %
August	29.6 °C	69 mm	60 %
September	30.3 °C	72 mm	65 %
October	30.4 °C	129 mm	73 %
November	29.5 °C	215 mm	84 %
December	28.4 °C	291 mm	90 %

Temperature month by month

Month	Avg high	Avg low	Mean	Record high	Record low	Days above 25 °C	Days above 30 °C
January	28.4 °C	24.3 °C	26.0 °C	30.8 °C	22.6 °C	31	1
February	28.6 °C	24.3 °C	26.1 °C	30.8 °C	22.6 °C	28	1
March	28.9 °C	24.6 °C	26.4 °C	31.4 °C	23.1 °C	31	2
April	29.2 °C	24.7 °C	26.6 °C	31.4 °C	22.5 °C	30	4
May	29.4 °C	24.7 °C	26.8 °C	31.5 °C	21.7 °C	31	6
June	29.2 °C	24.3 °C	26.5 °C	32.2 °C	21.3 °C	30	4
July	29.2 °C	23.8 °C	26.3 °C	32.2 °C	21.4 °C	31	4
August	29.6 °C	23.8 °C	26.5 °C	33.5 °C	20.9 °C	31	9
September	30.3 °C	24.2 °C	27.0 °C	33.4 °C	20.6 °C	30	16
October	30.4 °C	24.6 °C	27.1 °C	35.5 °C	22.3 °C	31	17
November	29.5 °C	24.7 °C	26.7 °C	34.3 °C	22.2 °C	30	10
December	28.4 °C	24.5 °C	26.1 °C	33.0 °C	22.7 °C	31	2

Rain, sun and wind month by month

Month	Rainfall	Wet days	Daylight	Cloud cover	Humidity	Wind	Sea temp
January	290 mm	28	12 h/day	89 %	87 %	15 km/h	28.5 °C
February	269 mm	26	12 h/day	90 %	87 %	14 km/h	28.6 °C
March	241 mm	27	12 h/day	86 %	87 %	14 km/h	29.0 °C
April	209 mm	26	12 h/day	81 %	87 %	12 km/h	29.5 °C
May	159 mm	23	12 h/day	69 %	86 %	10 km/h	29.7 °C
June	119 mm	20	12 h/day	62 %	85 %	11 km/h	29.5 °C
July	92 mm	17	12 h/day	61 %	83 %	10 km/h	29.0 °C
August	69 mm	16	12 h/day	60 %	80 %	10.0 km/h	28.8 °C
September	72 mm	15	12 h/day	65 %	79 %	10 km/h	29.0 °C
October	129 mm	20	12 h/day	73 %	80 %	11 km/h	29.4 °C
November	215 mm	24	12 h/day	84 %	84 %	13 km/h	29.5 °C
December	291 mm	26	12 h/day	90 %	87 %	16 km/h	29.0 °C

How Cilegon compares

The same four figures for nearby destinations, so the numbers above have something to be read against. Summer high is the warmest month's average high; winter low is the coldest month's average low.

Destination	Summer high	Winter low	Rain per year	Days above 25 °C
Cilegon	30 °C	24 °C	2,154 mm	365
Serang · Indonesia	31 °C	23 °C	1,941 mm	365
Pasarkemis · Indonesia	32 °C	22 °C	2,170 mm	365
Curug · Indonesia	32 °C	22 °C	2,166 mm	365
Teluknaga · Indonesia	32 °C	23 °C	2,011 mm	365
Tangerang · Indonesia	32 °C	22 °C	2,068 mm	365
Pamulang · Indonesia	32 °C	22 °C	2,115 mm	365

Where Cilegon ranks

Ranking	Position	Value
Warmest sea temperatures in Asia in November	27th of 50	30 °C
Warmest sea temperatures in the world in November	31st of 50	30 °C
Warmest sea temperatures in Asia in December	41st of 50	29 °C
Warmest sea temperatures in the world in December	50th of 50	29 °C

Planning a trip? See the best time to visit Cilegon.

QuestionsCommon questions about Cilegon’s climate

When is the best time to visit Cilegon?

That depends on what you want, so the honest answer is a comparison rather than a single month. January, February, December sit closest to 20 °C on average, October is the warmest month and August the driest. The month-by-month table above has the full picture.

How hot does Cilegon get?

In October, the warmest month, daily highs average 30 °C. About 77 days a year pass 30 °C. The highest value in the 1991–2020 record is 36 °C.

How cold does it get in winter?

Nights average 24 °C in July, the coldest month. Freezing nights are not part of a normal year here.

Which month is wettest in Cilegon?

December, averaging 291 mm over 26 days with rain. The driest month is August with 69 mm. The year as a whole averages 2,154 mm.

Are these figures a forecast?

No. They are 1991–2020 climate normals: the average of thirty years, which describes what a month is usually like in Cilegon rather than what any particular week will bring. Individual years can differ substantially from the normal.

Data sources and method

ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
Open-Meteo — Open-Meteo.com. CC BY 4.0
NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
GeoNames — GeoNames.org. CC BY 4.0

Normal period: 1991–2020
Data point: -6.014°, 106.054° (the coordinates the reanalysis values are taken for)
Dataset version: era5-1991-2020-scores1.1
Last processed: 1 August 2026

Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: monthly rankings, daylight hours, beach and comfort scores. Full formulas are on the methodology page.

Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.