Sibolga weather in September

In September, Sibolga sees average daytime highs of 28°C and overnight lows near 23°C, with 293 mm of rain across 23.2 wet days and about 12 hours of daylight. It is the 10th-warmest and 8th-wettest month of the year here.

Day-to-day highs hold fairly steady near 28°C through the month. The sky is clear or mostly clear about 1% of the time in September, and the air most often feels oppressive.

Daylight stretches from about 12 hours at the start of September to 12 hours by month's end. Set against the rest of the year, September is Sibolga's 8th-clearest and 5th-windiest month. For the whole year in context, see Sibolga's year-round climate.

Daytime high
28°
10th warmest
Overnight low
23°
2nd coldest
Rainfall
293 mm
23.2 wet days
Daylight
12 hours
6:19 AM – 6:19 PM
Cloud cover
89%
8th clearest
Wind
5 km/h
5th windiest
Solar energy
5.04 kWh/m²
Travel score
4.1
out of 10

Sibolga is city in North Sumatra Province, Indonesia.

Density
8,565/km²
people per km²
Founded
1700

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

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 28°C through the month.

A typical September day in Sibolga reaches about 28°C in the afternoon and slips back to 23°C overnight — a 4°C spread between the day's warmth and the night's chill. On most days the high lands between 26°C and 29°C. Set against its neighbours, September runs on par with August and on par with October.

20°23°25°28°30°151015202530
Avg high (°C)Avg low (°C)
12823
22823
32823
42823
52823
62823
72823
82823
92823
102823
112823
122823
132823
142823
152823
162823
172823
182823
192823
202823
212823
222823
232823
242823
252823
262823
272823
282823
292823
302823

How September really feels in Sibolga

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

September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Sibolga weather by month

How September compares with the rest of the year at a glance. September is the 10th-warmest and 8th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan28° / 24°33826.711.93.5
Feb29° / 24°31123.711.93.4
Mar29° / 24°36127.4123.2
Apr29° / 24°35726.7123.2
May29° / 24°26021.612.13.9
Jun29° / 24°15917.312.14.4
Jul28° / 24°19319.112.14.6
Aug28° / 23°28422.812.14.2
Sep28° / 23°29323.2124.1
Oct28° / 23°42826.1123.8
Nov27° / 23°50727.711.93.4
Dec28° / 24°43327.611.93.6

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 1% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 3% of September, with mostly cloudy or overcast conditions the remaining 96%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
1595
2595
3595
4595
5595
6595
7595
8595
9595
10595
11595
12496
13496
14496
15496
16496
17496
18496
19496
20496
21496
22496
23496
24496
25397
26397
27397
28397
29397
30496

Chance of precipitation in September

Any precipitation

Sibolga gets around 293 mm of rain over 23.2 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 77% and peaks near 82% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%80%151015202530
Rain chance (%)
177
276
376
476
575
675
775
875
975
1075
1174
1274
1375
1475
1575
1676
1776
1877
1978
2078
2179
2279
2380
2481
2581
2682
2782
2882
2982
3082

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the oppressive band about 99% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Muggy (%)Oppressive (%)Miserable (%)
11981
21981
31981
41981
51981
61981
71981
81981
91981
101981
111981
121981
131981
141981
151981
161990
1701000
1801000
1901000
2001000
210991
220991
230991
240991
250991
2601000
2701000
2801000
291990
301990

Wind in September

Winds average 5 km/h in September.

Across September, daily wind ranges from about 5 km/h on the calmest days to 5 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (km/h)Feels
15calm
25calm
35calm
45calm
55calm
65calm
75calm
85calm
95calm
105calm
115calm
125calm
135calm
145calm
155calm
165calm
175calm
185calm
195calm
205calm
215calm
225calm
235calm
245calm
255calm
265calm
275calm
285calm
295calm
305calm

Sunrise & sunset in September

DaylightNight

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

Days grow by about 0 minutes over September. Sunrise moves from 6:24 AM to 6:15 AM, and sunset from 6:26 PM to 6:14 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.06:246:26
212.06:236:25
312.06:236:25
412.06:236:24
512.06:226:24
612.06:226:24
712.06:226:23
812.06:216:23
912.06:216:22
1012.06:216:22
1112.06:216:22
1212.06:206:21
1312.06:206:21
1412.06:206:20
1512.06:196:20
1612.06:196:19
1712.06:196:19
1812.06:186:19
1912.06:186:18
2012.06:186:18
2112.06:176:17
2212.06:176:17
2312.06:176:17
2412.06:166:16
2512.06:166:16
2612.06:166:15
2712.06:156:15
2812.06:156:15
2912.06:156:14
3012.06:156:14

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.04 kWh/m².

For context, solar energy here swings from a low near 4.11 kWh/m² to a high of 5.45 kWh/m² in February across the year — September's 5.04 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.0Bright
25.0Bright
35.0Bright
45.0Bright
55.0Bright
65.0Bright
75.1Bright
85.1Bright
95.1Bright
105.1Bright
115.1Bright
125.1Bright
135.1Bright
145.1Bright
155.1Bright
165.1Bright
175.1Bright
185.0Bright
195.0Bright
205.0Bright
215.0Bright
225.0Bright
235.0Bright
245.0Bright
255.0Bright
264.9Bright
274.9Bright
284.9Bright
294.9Bright
304.9Bright
Planning a trip in September

Is September a good time to visit Sibolga?

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

4.1
Sightseeing
4th-best month of the year
4.3
Beach & pool
5th-best month of the year

September is a reasonable time to visit Sibolga for sightseeing.

What to pack for Sibolga in September

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

In September, Sibolga sees daytime highs around 28°C and nights near 23°C. Pack light clothes and rain gear. Worth having: sun protection. About 23 days see rain.

light clothesrain gearsun protection

Sea temperature near Sibolga in September

The nearest coast averages about 30°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 22 km away) is warmest in March at about 30°C and coldest in November 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
Feb30Tropical
Mar30Tropical
Apr30Tropical
May30Tropical
Jun30Tropical
Jul30Tropical
Aug30Tropical
Sep30Tropical
Oct29Tropical
Nov29Tropical
Dec29Tropical

UV index in Sibolga in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 14 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Sibolga peaks around February 18 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near August 11 at about 10 (extreme).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeFeb 18UV 14Aug 11UV 10
UV index (midday)Level
Jan12Extreme
Feb14Extreme
Mar13Extreme
Apr13Extreme
May11Extreme
Jun11Extreme
Jul11Extreme
Aug10Extreme
Sep14Extreme
Oct14Extreme
Nov12Extreme
Dec12Extreme

Air quality in Sibolga 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 Sibolga is worst in October — around 20 µg/m³ PM2.5 (moderate), about 1.7× the cleanest month (December, 12 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateOct 1220 µg/m³Dec 1112 µg/m³
PM2.5 (µg/m³)Level
Jan14Moderate
Feb18Moderate
Mar17Moderate
Apr15Moderate
May15Moderate
Jun14Moderate
Jul15Moderate
Aug14Moderate
Sep19Moderate
Oct20Moderate
Nov12Moderate
Dec12Moderate
Location & terrain

Where is Sibolga?

Sibolga sits at 1.7°N, 98.8°E, 6 m above sea level, in Indonesia. The nearest listed city is Tarutung, 37 km away.

Topography around Sibolga

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

Within 3 km, the terrain around Sibolga has significant variations in elevation — a maximum elevation change of 471 m around an average of 77 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 1,065 m; within 80 km, very significant variations in elevation — a maximum elevation change of 2,230 m.

The land around Sibolga is covered by trees (44%) and water (41%) within 3 km, trees (59%) and water (35%) within 16 km, and trees (58%) and water (36%) within 80 km.

3 km
471 m
16 km
1,065 m
80 km
2,230 m
treesgrasslandcroplandartificial surfacesbare terrainwatermangroves
September weather nearby: Tarutung 37 km · Barus 52 km · Padangsidempuan 68 km · Pangururan 97 km · Bandar 113 km · Rantauprapat 124 km · Sidikalang 124 km · Singkil 126 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 Sibolga (1.7402°, 98.7812°, elevation 6 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. 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).