The diving season in East Africa is from September to March, although the sheltered sides of Zanzibar & Pemba and on the Bay-side of Mafia the season is also good from June onwards.
Being near to the equator, the islands all warm year round with the average lows ranging around 21°C and the average highs around 30°C. This ensures a water temperature of being consistently between 25°C and 28°C (average 27°C/80°F). During summer, there are often cool windy conditions, resulting in pleasant sea breezes, particularly on the North and East coasts.
The best season for a vacation is from mid-June until the end of November, as well as from mid-December until mid-March. High season runs from July to September and from mid-December to mid-January. If you want to avoid the crowds (and higher prices) October is a nice, calm month, also weather-wise. March is also a good option, since the rainy season starts quite late since a few years but still being recognized as a rain-season-month, prices and flights are much cheaper. This is also a good time to see whales, sharks and turtles.
The Rainy Season, also referred to as the ‘Green Season’, runs from the end of March to May. Expect to have 12 days of rain in March/May and around 17 in April and humidity is high. Rain can be quite heavy, but it doesn’t necessarily rain every day and the hours of sun per day are still around 6-7 compared to 8 for other months. Also, in the last couple of years rain starts late, so before the end of March it’s pretty good. Note that some facilities might be closed during the rainy season. It can also be windy in this period, especially in May and June. When taking these factors into consideration, you could argue that late March to early June is not the best time to go.
There is also another, ‘minor’ rainy season in November to mid-December (10-12 days on average) but there are more sun-hours in a day. Short rains can occur in this period but are characterized by short showers which do not last long.
There are some months to keep in mind from a marine life perspective:
- August – October: migration of whales (Humpback whales and Sperm Whales)
- October – December: Nesting season begins for Hawksbill & Green Turtles, Whale shark season
- January – March: end of Nesting of Hawksbill & Green Turtles (hatching), Whale shark seasonThe diving season in East Africa is from September to March, although the sheltered sides of Zanzibar & Pemba and on the Bay-side of Mafia the season is also good from June onwards.