Climate averages 1991–2020
Isiolo weather
in September.
A hot, fairly dry month: the 3rd warmest and the 2nd driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a hot month in Isiolo: daytime highs average 29.2°C and nights cool to about 17.2°C. By daytime temperature it is the 3rd warmest of the 12 months.
Expect about 27 mm of rain on roughly 6 days, which makes September a fairly dry month (the 2nd driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 07 min on an average September day.
The nearest other city in this atlas is Meru (35 km away). In September its highs average 24.6°C, 4.6°C cooler than Isiolo, with 10 mm of rain.
Among the 37 cities listed in Kenya, Isiolo ranks 5th of 37 for the warmest September highs and joint 16th of 37 for the driest September (rainfall, lowest first). The mean September high of those 37 cities is 25.7°C; Isiolo is 3.5°C warmer than that mean.
From September to October, average highs fall by 0.2°C to 29.0°C, and monthly rainfall rises from 27 mm to 52 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Isiolo climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 28.1°C16.6°C | 16.6°C | 41 | 8.2 | 12.112 h |
| February | 29.4°C17.2°C | 17.2°C | 23 | 4.9 | 12.112 h |
| March | 29.5°C18.1°C | 18.1°C | 43 | 8.6 | 12.112 h |
| April | 28.7°C18.8°C | 18.8°C | 76 | 11.2 | 12.112 h |
| May | 28.9°C18.5°C | 18.5°C | 47 | 7.5 | 12.112 h |
| June | 28.0°C17.4°C | 17.4°C | 28 | 5.6 | 12.112 h |
| July | 27.2°C16.7°C | 16.7°C | 38 | 7.8 | 12.112 h |
| August | 27.7°C16.7°C | 16.7°C | 40 | 9.0 | 12.112 h |
| September, selected | 29.2°C17.2°C | 17.2°C | 27 | 5.7 | 12.112 h |
| October | 29.0°C18.3°C | 18.3°C | 52 | 10.0 | 12.112 h |
| November | 26.2°C17.6°C | 17.6°C | 99 | 19.8 | 12.112 h |
| December | 26.7°C16.6°C | 16.6°C | 55 | 13.3 | 12.112 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Meru in SeptemberKenya · 35 kmHigh 24.6°C · Low 14.2°C · 10 mm rain
- Nanyuki in SeptemberKenya · 69 kmHigh 21.6°C · Low 12.3°C · 41 mm rain
- Nyeri in SeptemberKenya · 111 kmHigh 20.4°C · Low 10.9°C · 46 mm rain
- Karuri (Murang'A), Kenya in SeptemberKenya · 125 kmHigh 25.3°C · Low 14.5°C · 27 mm rain
- Thika in SeptemberKenya · 165 kmHigh 24.7°C · Low 13.7°C · 23 mm rain
- Naivasha in SeptemberKenya · 175 kmHigh 21.1°C · Low 12.0°C · 53 mm rain
- Ruiru in SeptemberKenya · 181 kmHigh 24.3°C · Low 13.2°C · 9.5 mm rain
- Nakuru in SeptemberKenya · 183 kmHigh 23.1°C · Low 11.6°C · 51 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Isiolo) is explained once on the Isiolo year overview and on the Sources, method and limits page.