Cilegon weather in January

In January, Cilegon sees average daytime highs of 29°C and overnight lows near 25°C, with 285 mm of rain across 28.6 wet days and about 12.3 hours of daylight. It is the 12th-warmest and 2nd-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 3% of the time in January, and the air most often feels oppressive.

Daylight stretches from about 12 h 18 min at the start of January to 12 h 18 min by month's end. Set against the rest of the year, January is Cilegon's 10th-clearest and 2nd-windiest month. For the whole year in context, see Cilegon's year-round climate.

Daytime high
29°
12th warmest
Overnight low
25°
4th coldest
Rainfall
285 mm
28.6 wet days
Daylight
12 h 18 min
5:56 AM – 6:14 PM
Cloud cover
87%
10th clearest
Wind
10 km/h
2nd windiest
Solar energy
4.91 kWh/m²
Travel score
3.1
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 January

Average highAverage lowShaded bands: 10–90% of days

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

A typical January 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, January runs on par with December and on par with February.

20°23°25°28°30°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 January really feels in Cilegon

Once humidity and wind are folded in, January 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 January is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Cilegon weather by month

How January compares with the rest of the year at a glance. January is the 12th-warmest and 2nd-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 January

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 3% of the time in January.

Beyond those clear spells, partly cloudy skies cover about 8% of January, with mostly cloudy or overcast conditions the remaining 89%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
11288
21288
31288
41288
51387
61387
71387
81387
91387
101387
111486
121486
131486
141387
151387
161387
171387
181288
191288
201189
211090
221090
231090
24892
25892
26892
27892
28793
29793
30793
31694

Chance of precipitation in January

Any precipitation

Cilegon gets around 285 mm of rain over 28.6 wet days in January. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 92% and peaks near 96% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%80%100%151015202531
Rain chance (%)
188
289
389
489
589
689
789
890
990
1090
1190
1291
1391
1491
1592
1692
1793
1893
1994
2094
2195
2295
2395
2496
2596
2696
2796
2896
2996
3096
3196

Humidity in January

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, January lands in the oppressive band about 67% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Oppressive (%)Miserable (%)
16832
26832
36931
46931
56931
66931
76931
86931
96931
106931
116931
126931
136931
146931
156832
166832
176733
186733
196634
206634
216634
226535
236535
246535
256535
266535
276535
286535
296634
306634
316634

Wind in January

Winds average 10 km/h in January.

Across January, daily wind ranges from about 9 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
111calm
211calm
311calm
411calm
510calm
610calm
710calm
810calm
910calm
1010calm
1110calm
1210calm
1310calm
1410calm
1510calm
1610calm
1710calm
1810calm
1910calm
209calm
219calm
229calm
239calm
249calm
259calm
269calm
279calm
289calm
299calm
309calm
319calm

Sunrise & sunset in January

DaylightNight

Daylight runs from about 12 h 18 min at the start of January 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 January. Sunrise moves from 5:49 AM to 6:01 AM, and sunset from 6:09 PM to 6:17 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
112.35:496:09
212.35:496:10
312.35:506:10
412.35:506:10
512.35:516:11
612.35:516:11
712.35:526:12
812.35:526:12
912.35:526:12
1012.35:536:13
1112.35:536:13
1212.35:546:13
1312.35:546:14
1412.35:556:14
1512.35:556:14
1612.35:566:14
1712.35:566:15
1812.35:576:15
1912.35:576:15
2012.35:576:15
2112.35:586:16
2212.35:586:16
2312.35:586:16
2412.35:596:16
2512.35:596:16
2612.36:006:17
2712.36:006:17
2812.36:006:17
2912.36:016:17
3012.36:016:17
3112.36:016:17

Solar energy in January

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in January, about 4.91 kWh/m².

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 — January's 4.91 kWh/m² sits near the bottom.

024151015202531
Solar energy (kWh/m²)Level
14.8Bright
24.8Bright
34.8Bright
44.8Bright
54.9Bright
64.9Bright
74.9Bright
84.9Bright
94.9Bright
104.9Bright
114.9Bright
124.9Bright
134.9Bright
144.9Bright
154.9Bright
164.9Bright
174.9Bright
184.9Bright
194.9Bright
204.9Bright
214.9Bright
224.9Bright
234.9Bright
244.9Bright
254.9Bright
264.9Bright
274.9Bright
284.9Bright
294.9Bright
304.9Bright
314.9Bright
Planning a trip in January

Hazard calendar for Cilegon

In seasonPeak

In January, 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 January a good time to visit Cilegon?

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

3.1
Sightseeing
9th-best month of the year
3.9
Beach & pool
11th-best month of the year

January is a weaker month for outdoor sightseeing in Cilegon.

What to pack for Cilegon in January

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

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

light clothesrain gearsun protection

Sea temperature near Cilegon in January

The nearest coast averages about 29°C in January — 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 January

LowModerateHighVery highExtreme

Clear-sky midday UV in January peaks around 13 (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 January

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where January 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
January 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).