Koidu weather in September

In September, Koidu sees average daytime highs of 28°C and overnight lows near 21°C, with 422 mm of rain across 28.8 wet days and about 12.1 hours of daylight. It is the 10th-warmest and 1st-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 0% of the time in September, and the air most often feels oppressive.

Daylight stretches from about 12 h 12 min at the start of September to 11 h 54 min by month's end. Set against the rest of the year, September is Koidu's 10th-clearest and 7th-windiest month. For the whole year in context, see Koidu's year-round climate.

Daytime high
28°
10th warmest
Overnight low
21°
7th coldest
Rainfall
422 mm
28.8 wet days
Daylight
12 hours
6:37 AM – 6:40 PM
Cloud cover
86%
10th clearest
Wind
5 km/h
7th windiest
Solar energy
4.13 kWh/m²
Travel score
3.3
out of 10

Koidu is city in Kono District, Sierra Leone.

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 Koidu reaches about 28°C in the afternoon and slips back to 21°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 25°C and 29°C. Set against its neighbours, September runs about 1°C warmer than August and about 1°C cooler than October.

20°23°25°28°30°151015202530
Avg high (°C)Avg low (°C)
12721
22721
32721
42721
52721
62721
72721
82721
92721
102721
112721
122821
132821
142821
152821
162821
172821
182821
192821
202821
212821
222821
232821
242821
252821
262821
272821
282821
292821
302821

How September really feels in Koidu

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.

Koidu weather by month

How September compares with the rest of the year at a glance. September is the 10th-warmest and 1st-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan32° / 20°112.411.64.9
Feb34° / 22°142.911.73.8
Mar33° / 23°6310.311.93.4
Apr32° / 23°10515.712.23.5
May30° / 23°23525.412.43.2
Jun28° / 22°3352812.53.3
Jul27° / 21°36929.312.53.5
Aug27° / 21°41929.712.33.4
Sep28° / 21°42228.812.13.3
Oct29° / 21°32229.511.83.1
Nov29° / 21°12916.411.64.5
Dec30° / 20°163.111.55.9

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 0% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 5% of September, with mostly cloudy or overcast conditions the remaining 95%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
1298
2298
3298
4298
5397
6397
7397
8397
9496
10496
11496
12496
13496
14595
15595
16595
17595
18595
19694
20694
21694
22694
23793
24793
25892
26892
27892
28991
29991
30991

Chance of precipitation in September

Any precipitation

Koidu gets around 422 mm of rain over 28.8 wet days in September, the wettest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 96% and peaks near 97% on the wettest days.

0%20%40%60%80%100%151015202530
Rain chance (%)
197
297
397
497
597
697
797
897
997
1097
1197
1297
1396
1496
1596
1696
1796
1896
1996
2096
2196
2296
2396
2496
2596
2696
2796
2896
2996
3096

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 77% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Muggy (%)Oppressive (%)
13367
23268
33169
43070
52971
62971
72872
82773
92773
102674
112575
122476
132476
142377
152377
162278
172278
182179
192179
202080
212080
221981
231981
241882
251882
261783
271684
281684
291585
301585

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
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
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 h 12 min at the start of September to 11 h 54 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 18 minutes over September. Sunrise moves from 6:39 AM to 6:35 AM, and sunset from 6:49 PM to 6:31 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.26:396:49
212.26:386:48
312.26:386:47
412.16:386:47
512.16:386:46
612.16:386:46
712.16:386:45
812.16:386:45
912.16:386:44
1012.16:386:43
1112.16:376:43
1212.16:376:42
1312.16:376:41
1412.16:376:41
1512.16:376:40
1612.06:376:40
1712.06:376:39
1812.06:376:38
1912.06:366:38
2012.06:366:37
2112.06:366:37
2212.06:366:36
2312.06:366:35
2412.06:366:35
2512.06:366:34
2612.06:366:34
2712.06:356:33
2811.96:356:32
2911.96:356:32
3011.96:356:31

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.13 kWh/m².

For context, solar energy here swings from a low near 3.45 kWh/m² to a high of 5.99 kWh/m² in February across the year — September's 4.13 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
13.7Moderate
23.8Moderate
33.8Moderate
43.8Moderate
53.8Moderate
63.9Moderate
73.9Moderate
83.9Moderate
94.0Moderate
104.0Moderate
114.0Bright
124.0Bright
134.1Bright
144.1Bright
154.1Bright
164.2Bright
174.2Bright
184.2Bright
194.2Bright
204.3Bright
214.3Bright
224.3Bright
234.3Bright
244.4Bright
254.4Bright
264.4Bright
274.5Bright
284.5Bright
294.5Bright
304.5Bright
Planning a trip in September

Hazard calendar for Koidu

In seasonPeak

In September, Koidu sits inside its monsoon season. The full year is below, with each hazard's peak months called out.

Koidu's monsoon runs May–October, when most of the year's rain falls.

Koidu sees seasonal dust haze (February–April), heaviest in April.

Monsoon
Dust
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Koidu?

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

3.3
Sightseeing
9th-best month of the year
3.6
Beach & pool
10th-best month of the year

September is a weaker month for outdoor sightseeing in Koidu.

What to pack for Koidu in September

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

In September, Koidu sees daytime highs around 28°C and nights near 21°C. Pack light clothes and rain gear. About 29 days see rain.

light clothesrain gear

UV index in Koidu 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 Koidu peaks around August 22 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 14 at about 8 (very high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highAug 22UV 13Dec 14UV 8
UV index (midday)Level
Jan10Very high
Feb12Extreme
Mar13Extreme
Apr11Extreme
May12Extreme
Jun12Extreme
Jul12Extreme
Aug13Extreme
Sep13Extreme
Oct12Extreme
Nov9Very high
Dec8Very high

Air quality in Koidu 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 Koidu is worst in March — around 233 µg/m³ PM2.5 (very unhealthy), about 25.9× the cleanest month (August, 9 µg/m³).

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

0306090120150180210240JanFebMarAprMayJunJulAugSepOctNovDecUnhealthyVery unhealthyUnhealthyModerateGoodModeratePoorMar 18221 µg/m³Aug 189 µg/m³
PM2.5 (µg/m³)Level
Jan90Unhealthy
Feb98Unhealthy
Mar233Very unhealthy
Apr151Very unhealthy
May27Moderate
Jun18Moderate
Jul11Good
Aug9Good
Sep10Good
Oct16Moderate
Nov22Moderate
Dec45Poor
Location & terrain

Where is Koidu?

Koidu sits at 8.6°N, 11.0°W, 381 m above sea level, in Sierra Leone. The nearest listed city is Segbwema, 72 km away.

SegbwemaKenemaFoya KamaraYende MillimouGueckedouKissidougouBoMakeni

Topography around Koidu

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

Within 3 km, the terrain around Koidu has only modest variations in elevation — a maximum elevation change of 136 m around an average of 379 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 392 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,783 m.

The land around Koidu is covered by grassland (42%), artificial surfaces (30%) and trees (25%) within 3 km, trees (63%) and grassland (35%) within 16 km, and trees (80%) within 80 km.

3 km
136 m
16 km
392 m
80 km
1,783 m
treesshrubsgrasslandartificial surfacesbare terrainwater
September weather nearby: Segbwema 72 km · Kenema 89 km · Foya Kamara 90 km · Yende Millimou 92 km · Gueckedou 93 km · Kissidougou 113 km · Bo 113 km · Makeni 121 km

Sierra Leone travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type D / G
230 V · 50 Hz
Prices
≈ 24% of US
price level, 2025
GDP per capita
$846
2025
Happiness
3.3 / 10
World Happiness, 2025
Safe drinking water
11%
of population, 2024
Homicide rate
2.2
per 100k, 2020
Road deaths
33
per 100k/yr, 2019
Income group
Low
World Bank
Religion
Muslim 77%Christian 23%

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 Koidu (8.6439°, -10.9714°, elevation 381 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. 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).