Isiolo weather in September

In September, Isiolo sees average daytime highs of 26°C and overnight lows near 16°C, with 27 mm of rain across 5.7 wet days and about 12 hours of daylight. It is the 5th-warmest and 11th-wettest month of the year here.

Day-to-day highs hold fairly steady near 26°C through the month. The sky is clear or mostly clear about 53% of the time in September, and the air most often feels dry.

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

Daytime high
26°
5th warmest
Overnight low
16°
6th coldest
Rainfall
27 mm
5.7 wet days
Daylight
12 hours
6:24 AM – 6:24 PM
Cloud cover
42%
1st clearest
Wind
9 km/h
1st windiest
Solar energy
6.7 kWh/m²
Travel score
7.6
out of 10

Isiolo is city.

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 26°C through the month.

A typical September day in Isiolo reaches about 26°C in the afternoon and slips back to 16°C overnight — a 11°C spread between the day's warmth and the night's chill. On most days the high lands between 24°C and 28°C. Set against its neighbours, September runs about 1°C warmer than August and on par with October.

10°15°20°25°30°151015202530
Avg high (°C)Avg low (°C)
12515
22515
32515
42515
52515
62515
72615
82615
92615
102615
112615
122615
132615
142615
152615
162615
172615
182615
192615
202616
212616
222616
232716
242716
252716
262716
272716
282716
292716
302716

Isiolo weather by month

How September compares with the rest of the year at a glance. September is the 5th-warmest and 11th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan26° / 15°418.2127.3
Feb27° / 15°234.9127.4
Mar27° / 16°438.6126.9
Apr27° / 17°7611.3126.4
May26° / 17°477.5127.2
Jun25° / 16°285.6127.5
Jul24° / 15°387.8127.3
Aug25° / 15°409.1127.1
Sep26° / 16°275.7127.6
Oct26° / 16°5310126.8
Nov24° / 16°9919.8125.5
Dec25° / 15°5513.3126.6

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 53% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 22% of September, with mostly cloudy or overcast conditions the remaining 25%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
16832
26931
37030
47129
57228
67228
77426
87426
97426
107525
117624
127624
137624
147723
157723
167723
177723
187723
197723
207723
217723
227723
237723
247723
257723
267723
277723
287624
297624
307624

Chance of precipitation in September

Any precipitation

Isiolo gets around 27 mm of rain over 5.7 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 20% and peaks near 32% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%151015202530
Rain chance (%)
132
231
330
428
527
626
725
823
922
1021
1120
1219
1318
1417
1516
1616
1715
1815
1915
2015
2115
2215
2315
2415
2516
2616
2717
2817
2918
3018

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the dry band about 83% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)
18119
28218
38218
48317
58317
68416
78416
88416
98416
108416
118416
128515
138515
148515
158515
168416
178416
188416
198416
208416
218416
228317
238317
248218
258119
268119
278020
287921
297723
307624

Wind in September

Winds average 9 km/h in September, the windiest month of the year.

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

051015151015202530
Wind speed (km/h)Feels
19calm
29calm
39calm
49calm
59calm
69calm
79calm
89calm
99calm
109calm
119calm
129calm
139calm
149calm
159calm
169calm
179calm
189calm
199calm
209calm
219calm
229calm
239calm
249calm
259calm
269calm
279calm
289calm
299calm
309calm

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
212.06:296:29
312.06:296:29
412.06:286:29
512.06:286:28
612.06:286:28
712.06:276:27
812.06:276:27
912.06:266:27
1012.06:266:26
1112.06:266:26
1212.06:256:26
1312.06:256:25
1412.06:256:25
1512.06:246:24
1612.06:246:24
1712.06:246:24
1812.06:236:23
1912.06:236:23
2012.06:226:23
2112.06:226:22
2212.06:226:22
2312.06:216:21
2412.06:216:21
2512.06:216:21
2612.06:206:20
2712.06:206:20
2812.06:206:20
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 6.7 kWh/m².

For context, solar energy here swings from a low near 5.36 kWh/m² to a high of 6.82 kWh/m² in February across the year — September's 6.7 kWh/m² sits near the top of that range.

0246151015202530
Solar energy (kWh/m²)Level
16.3Intense
26.3Intense
36.3Intense
46.4Intense
56.4Intense
66.4Intense
76.5Intense
86.5Intense
96.5Intense
106.6Intense
116.6Intense
126.6Intense
136.7Intense
146.7Intense
156.7Intense
166.8Intense
176.8Intense
186.8Intense
196.8Intense
206.8Intense
216.8Intense
226.8Intense
236.8Intense
246.8Intense
256.8Intense
266.8Intense
276.8Intense
286.8Intense
296.8Intense
306.8Intense
Planning a trip in September

Is September a good time to visit Isiolo?

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

7.6
Sightseeing
1st-best month of the year
7.2
Beach & pool
2nd-best month of the year

September is one of the better times to visit Isiolo for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Isiolo in September

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

In September, Isiolo sees daytime highs around 26°C and nights near 16°C. Pack sun protection. Worth having: light clothes. About 6 days see rain.

sun protectionlight clothes

UV index in Isiolo 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 Isiolo peaks around March 17 at about 16 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 19 at about 11 (extreme).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeMar 17UV 16Jun 19UV 11
UV index (midday)Level
Jan15Extreme
Feb15Extreme
Mar16Extreme
Apr15Extreme
May12Extreme
Jun10Extreme
Jul11Extreme
Aug12Extreme
Sep13Extreme
Oct14Extreme
Nov13Extreme
Dec12Extreme

Air quality in Isiolo 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 Isiolo is worst in February — around 32 µg/m³ PM2.5 (moderate), about 1.7× the cleanest month (September, 19 µg/m³).

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

010203040JanFebMarAprMayJunJulAugSepOctNovDecModerateFeb 1832 µg/m³Sep 1819 µg/m³
PM2.5 (µg/m³)Level
Jan30Moderate
Feb32Moderate
Mar31Moderate
Apr28Moderate
May25Moderate
Jun28Moderate
Jul27Moderate
Aug21Moderate
Sep19Moderate
Oct20Moderate
Nov29Moderate
Dec32Moderate
Location & terrain

Where is Isiolo?

Isiolo sits at 0.4°N, 37.6°E, 1,095 m above sea level, in Kenya. The nearest listed city is Meru, 35 km away.

NanyukiChukaEmbuKerugoyaGarba TulaKaratina

Topography around Isiolo

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

Within 3 km, the terrain around Isiolo has only modest variations in elevation — a maximum elevation change of 146 m around an average of 1,107 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 833 m; within 80 km, extreme variations in elevation — a maximum elevation change of 4,636 m.

The land around Isiolo is covered by grassland (39%), artificial surfaces (25%) and shrubs (24%) within 3 km, grassland (42%) and shrubs (39%) within 16 km, and shrubs (40%) and grassland (36%) within 80 km.

3 km
146 m
16 km
833 m
80 km
4,636 m
treesshrubsgrasslandcroplandartificial surfacesbare terrain
September weather nearby: Meru 35 km · Maua 42 km · Nanyuki 69 km · Chuka 77 km · Embu 100 km · Kerugoya 101 km · Garba Tula 106 km · Karatina 106 km

Kenya travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type G
240 V · 50 Hz
Prices
≈ 34% of US
price level, 2025
GDP per capita
$2,363
2025
Happiness
4.7 / 10
World Happiness, 2025
Homicide rate
4.9
per 100k, 2022
Road deaths
28.3
per 100k/yr, 2019
Income group
Lower middle
World Bank
English
High
EF EPI 593
Religion
Christian 86%Muslim 11%other 2%none 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 Isiolo (0.3546°, 37.5822°, elevation 1,095 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).