Weather in Zanzibar in August

How August compares

August is the 10th warmest month of the year in Zanzibar and ranks 93rd of 134 destinations we compare for August - see where else is hot in August. Against London's average high of 21.4°C in August, Zanzibar is 6.3°C warmer by day and 9.0°C warmer at night.

Daytime and night-time in August

The typical August day in Zanzibar peaks at 27.7°C, but that is an average: the warmest 10% of days reach 28.8°C or more. About 100% of days top 25°C and 1 in 333 pass 30°C. Nights average 22.5°C; one night in ten drops to 21.7°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest August day here reached 30.2°C (2020-08-29) and the coldest night 19.9°C (1996-08-07).

Rain in August

Some rain (4-8 rainy days): about 7 days with 1 mm or more, 24 mm in total. Year to year it varies a lot - the wettest August was 2002 with 56 mm, the driest 2004 with 10 mm. Humidity averages 76%.

Sea temperature in August

The sea averages 25.6°C - warm enough to swim (22°c+). Depending on the year it ranges from 25.0°C to 26.0°C. For the warmest sea here, come in March (29.0°C).

Sunshine and daylight

Around 7.0 hours of sunshine a day (estimated from cloud cover), 11.8 hours of daylight: the sun rises about 06:30 and sets about 18:25 local time in mid-August. Average cloud cover is 41%.

Is August 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 by UK standards, but relatively mild for Zanzibar

August is towards the cooler end of Zanzibar's year, but that is relative: average daytime highs are 6.3°C above London's August figure. Expect summer clothing to feel appropriate throughout the day, with loose, breathable fabrics more useful than heavy layers. Humidity averages 76%, so the warmth can feel close even when the temperature is not particularly high. Plan more active outings around the cooler parts of the day and keep midday flexible for shade or swimming. Nights average 22.5°C, which means evenings remain warm rather than offering the cool-down you might expect at home.

Some rain, with room for outdoor plans

Rain is a consideration rather than a reason to rule August out. About 7 days have measurable rain, so it makes sense to leave some flexibility rather than building every day around uninterrupted outdoor time. That figure does not mean those days are complete washouts, but it also cannot tell you when rain will arrive. Sunshine averages about 7 hours within 11.8 hours of daylight, leaving a useful amount of sun without implying cloudless skies. Pack a light waterproof alongside sun protection. August suits travellers who can adjust plans to the weather better than those who need every day to be entirely dry.

Comfortable swimming is a strong reason to go

The sea averages 25.6°C, making swimming a clear part of August's appeal rather than something to brave briefly. The year-to-year range of 25°C to 26°C also suggests little variation in water warmth. That makes the month a good fit if your priority is time in the water with warm weather around it. Sea temperature alone does not establish swimming conditions, so check local advice before entering. The bigger practical catch for a UK traveller is the flight from London, at about 10 hours. August offers a strong weather case for that journey, provided you are comfortable with humidity and occasional rain.