September weather forecast
Cotonou, Benin

September’s weather in Cotonou denotes a subtle transition from the wet season to less wet conditions. Indicating the start of a new trend, September records 99mm (3.9") of rainfall and an inadequate daily sunshine duration of 5.5 hours. A marginal upswing in the average low temperature is noted, paired with an increase in sea temperature to 26°C (78.8°F). The daylight hours shrink to 12.2, while the UV index remains steady at 12 units, outlining consistent weather conditions compared to the previous month.

Temperature

The arrival of September sees an average high-temperature of a still warm 28.4°C (83.1°F), hardly diverging from August's 27.8°C (82°F). Cotonou, during the nights of September, averages a temperature close to its daytime high, at a still moderately hot 23.6°C (74.5°F).

Heat index

The heat index value during September is calculated to be a tropical 33°C (91.4°F). Undertake extra safety actions, heat cramps and heat exhaustion are expected. Heatstroke may result from lengthy activity.
Metrics for the heat index primarily focus on shaded spots and light wind conditions. If exposed to direct sunlight, the heat index could climb by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', is a calculated temperature value of how hot it feels when the moisture in the air is factored in. The perception of temperature can be subjective, varying based on activity and individual heat sensitivity, influenced by factors like wind, attire, and metabolic variations. Understand that direct sun rays can influence the weather's impact, leading to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for babies and toddlers. Young children typically face greater hazards than adults because they do not sweat as much. Their larger skin surface in comparison to their little bodies and the high heat production from their active nature compounds their vulnerability.

Humidity

In Cotonou, the average relative humidity in September is 82%.

Rainfall

In Cotonou, Benin, during September, the rain falls for 8 days and regularly aggregates up to 99mm (3.9") of precipitation. Throughout the year, there are 75 rainfall days, and 1308mm (51.5") of precipitation is accumulated.

Sea temperature

In September, the average sea temperature is 26°C (78.8°F).
Note: Water temperature ranging from 25°C (77°F) to 29°C (84.2°F) is recognized as warm and pleasant by all, making water activities comfortable and delightful for long durations.

Daylight

In September, the average length of the day is 12h and 9min.
On the first day of the month, sunrise is at 06:43 and sunset at 18:57. On the last day of September, sunrise is at 06:38 and sunset at 18:42 WAT.

Sunshine

In September, the average sunshine is 5.5h.

UV index

February through May, August through October, with an average maximum UV index of 12, are months with the highest UV index in Cotonou. A UV Index reading of 11, and higher, represents an extreme threat to health from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: In September, the average maximum UV index of 12 translates into the following recommendations:
Carry out all crucial safety measures, unprotected skin may burn instantly. The Sun's UV radiation is most potent between the hours of 10 a.m. and 4 p.m. Try to avoid direct sunlight during this time. For effective sun eye protection, rely on sunglasses certified for UVA and UVB resistance. Even on a cloudy day, a sunscreen with at least a 30 SPF should be applied generously and frequently reapplied, including after a swim or outdoor exercise. Be wary! Reflections from sand and water make UV radiation more intense.