Cilegon weather in December

In December, Cilegon sees average daytime highs of 29°C and overnight lows near 25°C, with 293 mm of rain across 27.1 wet days and about 12.3 hours of daylight. It is the 10th-warmest and 1st-wettest month of the year here.

Day-to-day highs hold fairly steady near 29°C through the month. The sky is clear or mostly clear about 2% of the time in December, and the air most often feels oppressive.

Daylight stretches from about 12 h 18 min at the start of December to 12 h 18 min by month's end. Set against the rest of the year, December is Cilegon's 12th-clearest and 1st-windiest month. For the whole year in context, see Cilegon's year-round climate.

Daytime high
29°
10th warmest
Overnight low
25°
8th coldest
Rainfall
293 mm
27.1 wet days
Daylight
12 h 18 min
5:42 AM – 6:02 PM
Cloud cover
89%
12th clearest
Wind
11 km/h
1st windiest
Solar energy
4.69 kWh/m²
Travel score
3.2
out of 10

Cilegon is city in Banten Province, Indonesia.

Density
2,680/km²
people per km²
Founded
1999

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

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 29°C through the month.

A typical December day in Cilegon reaches about 29°C in the afternoon and slips back to 25°C overnight — a 4°C spread between the day's warmth and the night's chill. On most days the high lands between 27°C and 30°C. Set against its neighbours, December runs on par with November and on par with January.

20°25°30°35°151015202531
Avg high (°C)Avg low (°C)
12925
22925
32925
42925
52925
62925
72925
82925
92925
102925
112925
122925
132925
142925
152925
162925
172925
182925
192925
202925
212925
222925
232925
242925
252925
262925
272925
282925
292925
302925
312925

How December really feels in Cilegon

Once humidity and wind are folded in, December averages 31 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
31
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

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

Cilegon weather by month

How December compares with the rest of the year at a glance. December is the 10th-warmest and 1st-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan29° / 25°28528.612.33.1
Feb29° / 25°26126.112.23.0
Mar29° / 25°25128123.0
Apr30° / 26°21826.511.93.0
May30° / 26°16523.811.73.4
Jun30° / 25°12020.111.73.9
Jul29° / 25°9418.111.74.4
Aug29° / 24°701711.84.5
Sep30° / 25°7415.9124.3
Oct30° / 25°13420.312.13.7
Nov30° / 25°22325.212.33.2
Dec29° / 25°29327.112.33.2

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 2% of the time in December, the cloudiest month of the year.

Beyond those clear spells, partly cloudy skies cover about 6% of December, with mostly cloudy or overcast conditions the remaining 92%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
1892
2892
3793
4793
5892
6892
7892
8892
9892
10892
11793
12793
13793
14793
15793
16793
17793
18892
19892
20892
21892
22892
23991
24991
251090
261090
271090
281090
291090
301090
311189

Chance of precipitation in December

Any precipitation

Cilegon gets around 293 mm of rain over 27.1 wet days in December, the wettest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 87% and peaks near 88% on the wettest days.

0%20%40%60%80%100%151015202531
Rain chance (%)
187
287
387
487
587
688
788
888
988
1088
1188
1288
1388
1488
1588
1687
1787
1887
1986
2086
2186
2286
2386
2486
2586
2687
2787
2887
2987
3088
3188

Humidity in December

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, December lands in the oppressive band about 62% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Oppressive (%)Miserable (%)
15743
25743
35743
45743
55842
65842
75842
85842
95941
105941
115941
125941
136040
146040
156139
166139
176238
186337
196337
206436
216535
226535
236634
246634
256733
266733
276733
286733
296832
306832
316832

Wind in December

Winds average 11 km/h in December, the windiest month of the year.

Across December, daily wind ranges from about 10 km/h on the calmest days to 11 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (km/h)Feels
110calm
210calm
311calm
411calm
511calm
611calm
711calm
811calm
911calm
1011calm
1111calm
1211calm
1311calm
1411calm
1511calm
1611calm
1711calm
1811calm
1911calm
2011calm
2111calm
2211calm
2311calm
2411calm
2511calm
2611calm
2711calm
2811calm
2911calm
3011calm
3111calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 12 h 18 min at the start of December to 12 h 18 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 0 minutes over December. Sunrise moves from 5:36 AM to 5:49 AM, and sunset from 5:55 PM to 6:09 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
112.35:365:55
212.35:365:56
312.35:365:56
412.35:375:57
512.35:375:57
612.35:375:58
712.35:385:58
812.35:385:58
912.35:395:59
1012.35:395:59
1112.35:396:00
1212.35:406:00
1312.35:406:01
1412.35:416:01
1512.35:416:02
1612.35:426:02
1712.35:426:03
1812.35:426:03
1912.35:436:04
2012.35:436:04
2112.35:446:05
2212.35:446:05
2312.35:456:06
2412.35:456:06
2512.35:466:07
2612.35:466:07
2712.35:476:08
2812.35:476:08
2912.35:486:08
3012.35:486:09
3112.35:496:09

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 4.69 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 4.69 kWh/m² to a high of 6.03 kWh/m² in September across the year — December's 4.69 kWh/m² sits near the bottom.

024151015202531
Solar energy (kWh/m²)Level
14.9Bright
24.8Bright
34.8Bright
44.8Bright
54.8Bright
64.8Bright
74.8Bright
84.7Bright
94.7Bright
104.7Bright
114.7Bright
124.7Bright
134.7Bright
144.7Bright
154.7Bright
164.7Bright
174.7Bright
184.7Bright
194.7Bright
204.7Bright
214.7Bright
224.7Bright
234.7Bright
244.7Bright
254.7Bright
264.7Bright
274.7Bright
284.8Bright
294.8Bright
304.8Bright
314.8Bright
Planning a trip in December

Hazard calendar for Cilegon

In seasonPeak

In December, Cilegon sits inside its cyclone season. The full year is below, with each hazard's peak months called out.

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

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

Is December a good time to visit Cilegon?

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

3.2
Sightseeing
7th-best month of the year
4.1
Beach & pool
8th-best month of the year

December is a weaker month for outdoor sightseeing in Cilegon.

What to pack for Cilegon in December

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

In December, Cilegon sees daytime highs around 29°C and nights near 25°C. Pack light clothes and rain gear. Worth having: sun protection. About 27 days see rain.

light clothesrain gearsun protection

Sea temperature near Cilegon in December

The nearest coast averages about 29°C in December — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 17 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 Cilegon in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December 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 Cilegon peaks around March 14 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near November 16 at about 7 (high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highExtremeVery highMar 14UV 15Nov 16UV 7
UV index (midday)Level
Jan13Extreme
Feb13Extreme
Mar15Extreme
Apr11Extreme
May9Very high
Jun8Very high
Jul9Very high
Aug10Very high
Sep9Very high
Oct11Extreme
Nov6High
Dec12Extreme

Air quality in Cilegon in December

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where December falls, not just the annual average.

Air quality in Cilegon is worst in August — around 37 µg/m³ PM2.5 (poor), about 2.7× the cleanest month (December, 14 µg/m³).

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

010203040JanFebMarAprMayJunJulAugSepOctNovDecModerateModeratePoorModerateAug 2037 µg/m³Dec 2114 µg/m³
PM2.5 (µg/m³)Level
Jan16Moderate
Feb18Moderate
Mar17Moderate
Apr24Moderate
May36Poor
Jun33Moderate
Jul35Poor
Aug37Poor
Sep36Poor
Oct33Moderate
Nov22Moderate
Dec14Moderate
Location & terrain

Where is Cilegon?

Cilegon sits at 6.0°S, 106.1°E, 18 m above sea level, in Indonesia. The nearest listed city is Serang, 16 km away.

Topography around Cilegon

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

Within 3 km, the terrain around Cilegon has only modest variations in elevation — a maximum elevation change of 67 m around an average of 17 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 634 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,756 m.

The land around Cilegon is covered by artificial surfaces (48%) and trees (26%) within 3 km, trees (40%) and water (31%) within 16 km, and water (56%) and trees (30%) within 80 km.

3 km
67 m
16 km
634 m
80 km
1,756 m
treesgrasslandcroplandartificial surfacesbare terrainwater
December weather nearby: Serang 16 km · Pandeglang 33 km · Kresek 38 km · Rangkasbitung 44 km · Labuan 47 km · Pasarkemis 55 km · Cikupa 56 km · Sepatan 59 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 Cilegon (-6.0144°, 106.0542°, elevation 18 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).