Climate averages 1991–2020
Cotonou weather
in September.
A warm, wet month: the 10th warmest and the 8th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a warm month in Cotonou: daytime highs average 26.7°C and nights cool to about 24.0°C. By daytime temperature it is the 10th warmest of the 12 months.
Expect about 104 mm of rain on roughly 18 days, which makes September a wet month (the 8th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 10 min on an average September day.
The nearest other city in this atlas is Godomè (8 km away). In September its highs average 27.1°C, about as warm as Cotonou, with 141 mm of rain.
Among the 8 cities listed in Benin, Cotonou ranks 8th of 8 for the warmest September highs and 1st of 8 for the driest September (rainfall, lowest first). The mean September high of those 8 cities is 28.0°C; Cotonou is 1.2°C cooler than that mean.
From September to October, average highs rise by 1.0°C to 27.8°C, and monthly rainfall rises from 104 mm to 110 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
Cotonou climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 29.4°C25.3°C | 25.3°C | 21 | 6.5 | 11.812 h |
| February | 29.9°C26.1°C | 26.1°C | 27 | 7.9 | 11.912 h |
| March | 30.1°C26.7°C | 26.7°C | 48 | 12.5 | 12.112 h |
| April | 29.8°C26.6°C | 26.6°C | 73 | 15.7 | 12.312 h |
| May | 29.0°C25.9°C | 25.9°C | 164 | 23.3 | 12.412 h |
| June | 27.5°C24.7°C | 24.7°C | 259 | 26.1 | 12.512 h |
| July | 26.4°C24.0°C | 24.0°C | 132 | 18.9 | 12.512 h |
| August | 26.1°C23.6°C | 23.6°C | 73 | 13.3 | 12.312 h |
| September, selected | 26.7°C24.0°C | 24.0°C | 104 | 18.0 | 12.212 h |
| October | 27.8°C24.7°C | 24.7°C | 110 | 20.2 | 12.012 h |
| November | 28.8°C25.7°C | 25.7°C | 49 | 13.8 | 11.812 h |
| December | 29.3°C25.6°C | 25.6°C | 27 | 7.6 | 11.812 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
- Godomè in SeptemberBenin · 8 kmHigh 27.1°C · Low 23.9°C · 141 mm rain
- Ekpé in SeptemberBenin · 13 kmHigh 27.0°C · Low 23.9°C · 144 mm rain
- Porto-Novo in SeptemberBenin · 25 kmHigh 27.5°C · Low 23.5°C · 144 mm rain
- Irewe in SeptemberNigeria · 80 kmHigh 26.9°C · Low 23.9°C · 175 mm rain
- Alasia in SeptemberNigeria · 84 kmHigh 27.0°C · Low 23.5°C · 175 mm rain
- Ota in SeptemberNigeria · 97 kmHigh 27.9°C · Low 22.7°C · 202 mm rain
- Bohicon in SeptemberBenin · 98 kmHigh 28.9°C · Low 22.4°C · 160 mm rain
- Ifo in SeptemberNigeria · 99 kmHigh 28.2°C · Low 22.5°C · 202 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 Cotonou) is explained once on the Cotonou year overview and on the Sources, method and limits page.