Gunungsitoli weather in September

In September, Gunungsitoli sees average daytime highs of 29°C and overnight lows near 25°C, with 352 mm of rain across 27.3 wet days and about 12 hours of daylight. It is the 8th-warmest and 5th-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 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 Gunungsitoli's 9th-clearest and 3rd-windiest month. For the whole year in context, see Gunungsitoli's year-round climate.

Daytime high
29°
8th warmest
Overnight low
25°
5th coldest
Rainfall
352 mm
27.3 wet days
Daylight
12 hours
6:24 AM – 6:24 PM
Cloud cover
91%
9th clearest
Wind
5 km/h
3rd windiest
Solar energy
4.73 kWh/m²
Travel score
3.0
out of 10

Gunungsitoli is city in North Sumatra Province, Indonesia.

Density
487/km²
people per km²
Founded
2008

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 29°C through the month.

A typical September day in Gunungsitoli reaches about 29°C in the afternoon and slips back to 25°C overnight — a 5°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, September runs on par with August and on par with October.

20°25°30°35°151015202530
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

How September really feels in Gunungsitoli

Once humidity and wind are folded in, September averages 30 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
30
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

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

Gunungsitoli weather by month

How September compares with the rest of the year at a glance. September is the 8th-warmest and 5th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan30° / 25°2832611.93.1
Feb30° / 25°23523123.1
Mar30° / 25°31228.3122.7
Apr30° / 25°36028.2122.7
May30° / 25°28525.412.13.0
Jun30° / 25°23322.312.13.4
Jul30° / 25°26824.412.13.3
Aug29° / 25°33327123.1
Sep29° / 25°35227.3123.0
Oct29° / 25°47128.8123.0
Nov29° / 25°51128.711.92.9
Dec29° / 25°39928.411.93.0

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 2% of September, with mostly cloudy or overcast conditions the remaining 97%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
1496
2496
3496
4496
5496
6496
7496
8496
9496
10496
11397
12397
13397
14397
15397
16397
17397
18397
19397
20298
21298
22298
23298
24298
25298
26298
27298
28298
29397
30397

Chance of precipitation in September

Any precipitation

Gunungsitoli gets around 352 mm of rain over 27.3 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 91% and peaks near 93% on the wettest days.

0%20%40%60%80%100%151015202530
Rain chance (%)
190
290
390
490
590
690
790
890
990
1089
1189
1289
1389
1489
1589
1689
1790
1890
1990
2091
2191
2291
2392
2492
2592
2692
2793
2893
2993
3093

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 51% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Oppressive (%)Miserable (%)
15050
25050
35050
45050
55050
65149
75149
85149
95248
105248
115248
125248
135248
145248
155248
165248
175248
185149
195149
205149
215149
225050
235050
245050
255050
265050
274951
285050
295050
305050

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 6 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
266calm
276calm
286calm
296calm
306calm

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 6:29 AM to 6:19 AM, and sunset from 6:30 PM to 6:19 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.06:296:30
212.06:286:30
312.06:286:29
412.06:286:29
512.06:276:28
612.06:276:28
712.06:276:28
812.06:266:27
912.06:266:27
1012.06:266:27
1112.06:256:26
1212.06:256:26
1312.06:256:25
1412.06:246:25
1512.06:246:24
1612.06:246:24
1712.06:236:24
1812.06:236:23
1912.06:236:23
2012.06:226:22
2112.06:226:22
2212.06:226:22
2312.06:216:21
2412.06:216:21
2512.06:216:20
2612.06:206:20
2712.06:206:20
2812.06:206:19
2912.06:196:19
3012.06:196:19

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.73 kWh/m².

For context, solar energy here swings from a low near 3.92 kWh/m² to a high of 5.31 kWh/m² in February across the year — September's 4.73 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.6Bright
24.6Bright
34.7Bright
44.7Bright
54.7Bright
64.7Bright
74.7Bright
84.7Bright
94.8Bright
104.8Bright
114.8Bright
124.8Bright
134.8Bright
144.8Bright
154.8Bright
164.8Bright
174.8Bright
184.8Bright
194.8Bright
204.8Bright
214.7Bright
224.7Bright
234.7Bright
244.7Bright
254.7Bright
264.7Bright
274.7Bright
284.6Bright
294.6Bright
304.6Bright
Planning a trip in September

Is September a good time to visit Gunungsitoli?

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

3.0
Sightseeing
6th-best month of the year
3.9
Beach & pool
7th-best month of the year

September is a weaker month for outdoor sightseeing in Gunungsitoli.

What to pack for Gunungsitoli in September

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

In September, Gunungsitoli 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 Gunungsitoli in September

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

The sea offshore is warmest in May 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
Sep29Tropical
Oct29Tropical
Nov29Tropical
Dec29Tropical

UV index in Gunungsitoli 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 Gunungsitoli peaks around February 19 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 11 at about 11 (extreme).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeFeb 19UV 14Jul 11UV 11
UV index (midday)Level
Jan13Extreme
Feb14Extreme
Mar14Extreme
Apr14Extreme
May12Extreme
Jun11Extreme
Jul11Extreme
Aug12Extreme
Sep14Extreme
Oct14Extreme
Nov12Extreme
Dec12Extreme
Location & terrain

Where is Gunungsitoli?

Gunungsitoli sits at 1.3°N, 97.6°E, 14 m above sea level, in Indonesia. The nearest listed city is Lahewa, 51 km away.

Topography around Gunungsitoli

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

Within 3 km, the terrain around Gunungsitoli has only modest variations in elevation — a maximum elevation change of 223 m around an average of 42 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 367 m; within 80 km, large variations in elevation — a maximum elevation change of 834 m.

The land around Gunungsitoli is covered by trees (51%) and water (37%) within 3 km, trees (50%) and water (48%) within 16 km, and water (79%) and trees (21%) within 80 km.

3 km
223 m
16 km
367 m
80 km
834 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Lahewa 51 km · Teluk Dalam 82 km · Singkil 113 km · Barus 118 km · Sibolga 139 km · Subulussalam 156 km · Tarutung 170 km · Sidikalang 180 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 Gunungsitoli (1.2888°, 97.6143°, elevation 14 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. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).