Serang weather in January

In January, Serang sees average daytime highs of 29°C and overnight lows near 25°C, with 277 mm of rain across 28.3 wet days and about 12.3 hours of daylight. It is the 12th-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 3% of the time in January, and the air most often feels miserable.

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 Serang's 10th-clearest and 2nd-windiest month. For the whole year in context, see Serang's year-round climate.

Daytime high
29°
12th warmest
Overnight low
25°
5th coldest
Rainfall
277 mm
28.3 wet days
Daylight
12 h 18 min
5:55 AM – 6:14 PM
Cloud cover
86%
10th clearest
Wind
9 km/h
2nd windiest
Solar energy
4.79 kWh/m²
Travel score
2.9
out of 10

Serang is city in Banten Province, Indonesia.

Density
2,755/km²
people per km²
Founded
2007

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 Serang 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 28°C and 31°C. Set against its neighbours, January runs on par with December and on par with February.

20°25°30°35°151015202531
Avg high (°C)Avg low (°C)
13025
23025
33025
43025
53025
63025
73025
83025
93025
103025
113025
123025
133025
143025
153025
162925
172925
182925
192925
202925
212925
222925
232925
242925
252925
262925
272925
282925
292925
302925
312925

How January really feels in Serang

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.

Serang weather by month

How January compares with the rest of the year at a glance. January is the 12th-warmest and 1st-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan29° / 25°27728.312.32.9
Feb30° / 25°25526.312.22.8
Mar30° / 26°23627.5122.8
Apr31° / 26°19025.511.92.9
May31° / 26°13321.611.73.4
Jun30° / 25°10017.611.73.9
Jul30° / 25°731511.74.5
Aug30° / 25°5012.811.84.7
Sep31° / 25°6214.2124.2
Oct31° / 26°11920.712.13.4
Nov30° / 26°19225.812.32.9
Dec30° / 26°25626.312.33.0

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
111387
121387
131387
141387
151387
161387
171189
181189
191189
201090
211090
22991
23991
24892
25892
26892
27892
28694
29694
30694
31694

Chance of precipitation in January

Any precipitation

Serang gets around 277 mm of rain over 28.3 wet days in January, the wettest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 91% 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 (%)
186
286
387
487
587
687
788
888
988
1089
1189
1290
1390
1491
1591
1692
1792
1893
1993
2094
2194
2294
2395
2495
2595
2695
2796
2896
2996
3096
3196

Humidity in January

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, January lands in the miserable band about 66% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Oppressive (%)Miserable (%)
13466
23565
33565
43565
53565
63565
73565
83565
93565
103565
113565
123565
133565
143466
153466
163466
173466
183466
193466
203466
213466
223367
233367
243367
253367
263367
273367
283367
293367
303367
313367

Wind in January

Winds average 9 km/h in January.

Across January, daily wind ranges from about 9 km/h on the calmest days to 10 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (km/h)Feels
110calm
210calm
310calm
410calm
510calm
610calm
79calm
89calm
99calm
109calm
119calm
129calm
139calm
149calm
159calm
169calm
179calm
189calm
199calm
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 5:48 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)
112.35:486:09
212.35:496:09
312.35:496:10
412.35:506:10
512.35:506:11
612.35:506:11
712.35:516:11
812.35:516:12
912.35:526:12
1012.35:526:12
1112.35:536:13
1212.35:536:13
1312.35:546:13
1412.35:546:14
1512.35:556:14
1612.35:556:14
1712.35:566:15
1812.35:566:15
1912.35:566:15
2012.35:576:15
2112.35:576:15
2212.35:586:16
2312.35:586:16
2412.35:586:16
2512.35:596:16
2612.35:596:16
2712.35:596:16
2812.36:006:16
2912.36:006:17
3012.36:006:17
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 4.79 kWh/m².

For context, solar energy here swings from a low near 4.66 kWh/m² to a high of 6 kWh/m² in September across the year — January's 4.79 kWh/m² sits near the bottom.

024151015202531
Solar energy (kWh/m²)Level
14.7Bright
24.7Bright
34.8Bright
44.8Bright
54.8Bright
64.8Bright
74.8Bright
84.8Bright
94.8Bright
104.8Bright
114.8Bright
124.8Bright
134.8Bright
144.8Bright
154.8Bright
164.8Bright
174.8Bright
184.8Bright
194.8Bright
204.8Bright
214.8Bright
224.8Bright
234.8Bright
244.8Bright
254.8Bright
264.8Bright
274.8Bright
284.8Bright
294.8Bright
304.8Bright
314.8Bright
Planning a trip in January

Hazard calendar for Serang

In seasonPeak

In January, Serang sits inside its cyclone and rainy season season. The full year is below, with each hazard's peak months called out.

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

Serang's rainy season runs November–May, when most of the year's rain falls.

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

Is January a good time to visit Serang?

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

2.9
Sightseeing
8th-best month of the year
3.9
Beach & pool
11th-best month of the year

January is a weaker month for outdoor sightseeing in Serang.

What to pack for Serang in January

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

In January, Serang sees daytime highs around 29°C and nights near 25°C. Pack light clothes and rain gear. Worth having: sun protection. About 28 days see rain.

light clothesrain gearsun protection

Sea temperature near Serang 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 27 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 Serang 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 Serang 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 Serang 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 Serang is worst in May — around 74 µg/m³ PM2.5 (unhealthy), about 1.9× the cleanest month (December, 38 µg/m³).

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

020406080JanFebMarAprMayJunJulAugSepOctNovDecPoorUnhealthyPoorMay 2073 µg/m³Dec 2438 µg/m³
PM2.5 (µg/m³)Level
Jan39Poor
Feb41Poor
Mar51Poor
Apr62Unhealthy
May74Unhealthy
Jun69Unhealthy
Jul67Unhealthy
Aug67Unhealthy
Sep70Unhealthy
Oct69Unhealthy
Nov61Unhealthy
Dec38Poor
Location & terrain

Where is Serang?

Serang sits at 6.1°S, 106.2°E, 29 m above sea level, in Indonesia. The nearest listed city is Cilegon, 16 km away.

Topography around Serang

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

Within 3 km, the terrain around Serang has only modest variations in elevation — a maximum elevation change of 43 m around an average of 29 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 489 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,912 m.

The land around Serang is covered by artificial surfaces (61%) and trees (29%) within 3 km, trees (45%) and cropland (24%) within 16 km, and water (50%) and trees (35%) within 80 km.

3 km
43 m
16 km
489 m
80 km
1,912 m
treesgrasslandcroplandartificial surfaceswaterwetland
January weather nearby: Cilegon 16 km · Pandeglang 22 km · Kresek 25 km · Rangkasbitung 29 km · Cikupa 41 km · Pasarkemis 42 km · Labuan 46 km · Sepatan 47 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 Serang (-6.1153°, 106.1542°, elevation 29 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).