Poso weather in September

In September, Poso sees average daytime highs of 28°C and overnight lows near 20°C, with 165 mm of rain across 17.6 wet days and about 12 hours of daylight. It is the 1st-warmest and 11th-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 15% of the time in September, and the air most often feels muggy.

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 Poso's 1st-clearest and 3rd-windiest month. For the whole year in context, see Poso's year-round climate.

Daytime high
28°
1st warmest
Overnight low
20°
3rd coldest
Rainfall
165 mm
17.6 wet days
Daylight
12 hours
5:52 AM – 5:51 PM
Cloud cover
67%
1st clearest
Wind
5 km/h
3rd windiest
Solar energy
5.79 kWh/m²
Travel score
4.7
out of 10

Poso is administrative seat of Poso Regency.

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 Poso reaches about 28°C in the afternoon and slips back to 20°C overnight — a 8°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, September runs on par with August and on par with October.

15°20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
12820
22820
32820
42820
52820
62820
72820
82820
92820
102820
112820
122820
132820
142820
152820
162820
172820
182820
192820
202820
212820
222820
232820
242821
252821
262821
272821
282821
292821
302821

Poso weather by month

How September compares with the rest of the year at a glance. September is the 1st-warmest and 11th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan27° / 20°27827.412.13.6
Feb27° / 20°24125123.7
Mar27° / 21°36028.6123.5
Apr27° / 21°43329.2123.3
May28° / 21°35429.211.93.5
Jun27° / 21°28825.811.93.9
Jul27° / 21°20422.611.94.5
Aug28° / 21°15919.1125.0
Sep28° / 20°16517.6124.7
Oct28° / 21°24522.5124.0
Nov28° / 21°35028.212.13.5
Dec27° / 21°34530.312.13.3

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 15% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 19% of September, with mostly cloudy or overcast conditions the remaining 65%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
13862
23961
33862
43961
53862
63862
73763
83763
93763
103763
113664
123664
133565
143565
153466
163466
173466
183466
193367
203367
213466
223466
233466
243367
253268
263268
273268
283169
293169
302971

Chance of precipitation in September

Any precipitation

Poso gets around 165 mm of rain over 17.6 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 59% and peaks near 64% on the wettest days.

0%20%40%60%151015202530
Rain chance (%)
161
261
360
459
559
658
758
857
957
1056
1156
1256
1356
1456
1557
1657
1758
1858
1959
2059
2159
2260
2360
2461
2561
2662
2763
2863
2964
3064

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the muggy band about 80% of days. Sticky, muggy-or-worse air turns up on roughly 87% of them.

0%25%50%75%100%151015202530
Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1111853
2111853
3111853
4112843
5112834
6212824
7213814
8213814
9213814
10213814
11214804
12214795
13214795
14214795
15213796
16213796
17213796
18212797
19212797
20212797
21111808
22111808
23110818
24110809
2519819
26198010
27198010
28188011
29188011
30287812

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 5:58 AM to 5:46 AM, and sunset from 5:56 PM to 5:47 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.05:585:56
212.05:575:56
312.05:575:55
412.05:565:55
512.05:565:55
612.05:565:54
712.05:555:54
812.05:555:54
912.05:545:53
1012.05:545:53
1112.05:545:53
1212.05:535:52
1312.05:535:52
1412.05:525:52
1512.05:525:51
1612.05:525:51
1712.05:515:51
1812.05:515:50
1912.05:505:50
2012.05:505:50
2112.05:495:49
2212.05:495:49
2312.05:495:49
2412.05:485:48
2512.05:485:48
2612.05:475:48
2712.05:475:48
2812.05:475:47
2912.05:465:47
3012.05:465:47

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.79 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 4.3 kWh/m² to a high of 5.79 kWh/m² in September across the year — September's 5.79 kWh/m² sits near the top of that range.

0246151015202530
Solar energy (kWh/m²)Level
15.5Bright
25.6Bright
35.6Bright
45.6Bright
55.7Bright
65.7Bright
75.7Bright
85.7Bright
95.7Bright
105.7Bright
115.8Bright
125.8Bright
135.8Bright
145.8Bright
155.8Bright
165.8Bright
175.8Bright
185.8Bright
195.8Bright
205.8Bright
215.8Bright
225.8Bright
235.8Bright
245.8Bright
255.8Bright
265.8Bright
275.8Bright
285.8Bright
295.8Bright
305.8Bright
Planning a trip in September

Is September a good time to visit Poso?

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

4.7
Sightseeing
2nd-best month of the year
5.5
Beach & pool
1st-best month of the year

September is a reasonable time to visit Poso for sightseeing.

What to pack for Poso in September

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

In September, Poso sees daytime highs around 28°C and nights near 20°C. Pack light clothes and rain gear. Worth having: sun protection. About 18 days see rain.

light clothesrain gearsun protection

Sea temperature near Poso 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 14 km away) is warmest in April at about 30°C and coldest in February 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
Jan30Tropical
Feb29Tropical
Mar30Tropical
Apr30Tropical
May30Tropical
Jun30Tropical
Jul30Tropical
Aug30Tropical
Sep30Tropical
Oct30Tropical
Nov30Tropical
Dec30Tropical

UV index in Poso in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September 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 Poso peaks around February 19 at about 16 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 21 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 16Jun 21UV 11
UV index (midday)Level
Jan15Extreme
Feb16Extreme
Mar15Extreme
Apr14Extreme
May13Extreme
Jun11Extreme
Jul12Extreme
Aug13Extreme
Sep13Extreme
Oct14Extreme
Nov13Extreme
Dec12Extreme

Air quality in Poso 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 Poso is worst in October — around 17 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (February, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodOct 1417 µg/m³Feb 108 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb8Good
Mar8Good
Apr9Good
May9Good
Jun9Good
Jul9Good
Aug9Good
Sep14Moderate
Oct17Moderate
Nov12Good
Dec9Good
Location & terrain

Where is Poso?

Poso sits at 1.4°S, 120.8°E, 10 m above sea level, in Indonesia. The nearest listed city is Palu, 112 km away.

Majene

Topography around Poso

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

Within 3 km, the terrain around Poso has only modest variations in elevation — a maximum elevation change of 229 m around an average of 47 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 737 m; within 80 km, extreme variations in elevation — a maximum elevation change of 2,772 m.

The land around Poso is covered by trees (65%) and water (20%) within 3 km, trees (52%) and water (43%) within 16 km, and trees (65%) and water (30%) within 80 km.

3 km
229 m
16 km
737 m
80 km
2,772 m
treesgrasslandcroplandartificial surfaceswatermangroves
September weather nearby: Palu 112 km · Masamba 137 km · Bungku 186 km · Palopo 188 km · Rantepao 199 km · Luwuk 232 km · Polewali 275 km · Majene 310 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 Poso (-1.3959°, 120.7524°, elevation 10 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).