September weather forecast
Bissau, Guinea-Bissau

In September, Bissau witnesses a significant decline in rainfall to 435mm (17.13"), signaling the nearing end of the wet season. Sea temperature remains stable at 28.3°C (82.9°F), feeding into the overall temperature and rainfall. The daylight hours also shrink slightly, though they largely remain consistent with previous months. September represents a gradient shift in Bissau's climate, gradually transitioning into milder weather. The city retains its lively atmosphere while preparing for an approaching dry season.

Temperature

Bissau's September showcases an average high-temperature of a still hot 30°C (86°F), mirroring the conditions of the previous month. Bissau's average low-temperature for the month of September records at a pleasant 22.8°C (73°F).

Rainfall

In Bissau, in September, during 19 rainfall days, 435mm (17.13") of precipitation is typically accumulated. In Bissau, during the entire year, the rain falls for 86 days and collects up to 2023mm (79.65") of precipitation.

Sea temperature

In Bissau, in September, the average water temperature is 28.3°C (82.9°F).
Note: For swimming, diving, and enjoying other water activities, the range of 25°C (77°F) to 29°C (84.2°F) in water temperature is considered ideal, offering pleasure for extended periods without discomfort.

Daylight

In Bissau, Guinea-Bissau, the average length of the day in September is 12h and 11min.
On the first day of September, sunrise is at 06:52 and sunset at 19:12. On the last day of the month, sunrise is at 06:51 and sunset at 18:53 GMT.

Sunshine

In Bissau, the average sunshine in September is 6h.

UV index

February through September, with an average maximum UV index of 12, are months with the highest UV index in Bissau, Guinea-Bissau. A UV Index estimate of 11, and higher, represents an extreme health hazard from unprotected exposure to Sun's UV rays for the average person.
Note: In September, the maximum UV index of 12 translates into these guidelines:
Employ all critical precautions. Guarding against sun damage is essential. Stay in the shade and limit direct sun exposure between 10 a.m. and 4 p.m., when UV radiation is at its strongest. Remember, however, that not all shade structures provide full sun protection. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays. Even on a cloudy day, sunscreen with a minimum SPF of 30 should be used liberally and reapplied often, especially after a swim or outdoor activity. Be mindful! Sand and water reflections can up the Sun's UV exposure.