September weather forecast
Libreville, Gabon

September, the first month of the autumn in Libreville, is still a warm month, with temperature in the range of an average low of 23.5°C (74.3°F) and an average high of 27.8°C (82°F).

Temperature

In September, the average high-temperature is relatively the same as in August - a still warm 27.8°C (82°F). The average low-temperature, in Libreville, is 23.5°C (74.3°F).

Heat index

In September, the average heat index is computed to be a tropical 32°C (89.6°F). Exhaustion is likely with prolonged exposure and activity. Sustaining activity may result in heat cramps.
Take into consideration that the heat index values are calculated for shade and light wind conditions. With exposure to direct sunlight, the heat index may be increased by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel', 'feels like', 'felt air temperature', or 'apparent temperature', is a measure that combines air temperature and relative humidity into a single value that indicates how hot the weather feels. Additional factors like activity, wind, clothing, and differences in body mass, height, and shape affect individual temperature impact. Be aware that direct exposure to sunlight increases heat impact and may raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.

Humidity

The average relative humidity in September is 83%.

Rainfall

In Libreville, during September, the rain falls for 17.7 days and regularly aggregates up to 76mm (2.99") of precipitation. In Libreville, during the entire year, the rain falls for 274.1 days and collects up to 1477mm (58.15") of precipitation.

Sea temperature

In Libreville, the average seawater temperature in September is 25.7°C (78.3°F).
Note: For swimming, diving, and other water activities, temperatures between 25°C (77°F) and 29°C (84.2°F) are perceived as very enjoyable and pleasurable for prolonged periods without feeling uncomfortable.

Daylight

In September, the average length of the day is 12h and 7min.
On the first day of the month, sunrise is at 06:18 and sunset at 18:25. On the last day of September, in Libreville, sunrise is at 06:08 and sunset at 18:15 WAT.

Sunshine

With an average of 5.1h of sunshine, September has the least sunshine of the year in Libreville.

UV index

June through October, with an average maximum UV index of 6, are months with the lowest UV index in Libreville. A UV Index reading of 6 to 7 represents a high health vulnerability from unsafe exposure to UV radiation for average individuals.
Note: In September, the average maximum UV index of 6 translate into the following recommendations:
Take precautions against overexposure. Protection against sun damage is needed. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun. Caution! The reflection of sand and water significantly increases the intensity of the Sun's UV radiation.