Weather in Zanzibar in September

How September compares

September is the 8th warmest month of the year in Zanzibar and ranks 40th of 134 destinations we compare for September - see where else is hot in September. Against London's average high of 18.6°C in September, Zanzibar is 10.0°C warmer by day and 11.7°C warmer at night.

Daytime and night-time in September

The typical September day in Zanzibar peaks at 28.6°C, but that is an average: the warmest 10% of days reach 29.7°C or more. About 100% of days top 25°C and 1 in 20 pass 30°C. Nights average 22.9°C; one night in ten drops to 21.9°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest September day here reached 31.5°C (2020-09-29) and the coldest night 20.2°C (1996-09-24).

Rain in September

Some rain (4-8 rainy days): about 7 days with 1 mm or more, 23 mm in total. Year to year it varies a lot - the wettest September was 2018 with 66 mm, the driest 2001 with 3 mm. Humidity averages 75%, which makes the heat feel heavier than the thermometer suggests.

Sea temperature in September

The sea averages 25.9°C - warm enough to swim (22°c+). Depending on the year it ranges from 25.3°C to 26.3°C. For the warmest sea here, come in March (29.0°C).

Sunshine and daylight

Around 8.0 hours of sunshine a day (estimated from cloud cover), 12.0 hours of daylight: the sun rises about 06:16 and sets about 18:21 local time in mid-September. Average cloud cover is 34%.

Is September a good time to visit Zanzibar?

Yes - it is one of the better months: hot days, manageable rain and long sunny days. The best months for Zanzibar on our scoring are September, August, July; months averaging 25°C or more: Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec.

Hot days, with little cooling after dark

Expect dependable warmth rather than frequent extreme heat: every September day in the figures reaches 25°C, while only 5% reach 30°C. The catch is humidity at 75%, which can make moving around feel more tiring than the temperature alone suggests. Keep active plans for the cooler parts of the day and leave room for shade around midday. Loose, breathable clothing is a better starting point than heavy layers, and warm nights mean you should not expect much relief after sunset. If you sleep badly in the heat, prioritise a room with effective cooling. September suits travellers who like warmth throughout the day, not those seeking crisp evenings.

Plenty of sunshine, but allow for rain

September offers about 8 hours of sunshine within 12 hours of daylight, giving you plenty of scope for time outdoors without implying cloudless skies. There are about 7 rainy days, so a completely dry holiday is not something to count on. Keep outdoor plans flexible and pack a light waterproof rather than treating rain as a reason to rule the month out. The figures do not tell you when rain will fall or how long it will last, so avoid assuming it will always pass quickly. Sun protection still belongs in your daily routine, and shade breaks make sense even when cloud takes the edge off the sunshine.