The short answer: June to October is the most reliable stretch — dry, breezy and cooler — and January to February is the best of the hot months. April is the one month we would genuinely steer you away from. Everything else is a trade-off rather than a mistake, and this page is about which trade-off you are making.
Two monsoons, and the rain that falls between them
Zanzibar has no winter. What it has is two monsoons that swap over twice a year, and two rainy seasons that fall in the gaps between them.
- Kaskazi, the north-east monsoon, runs roughly from December to March. Hot, humid, and light on wind — 32–33 °C by day, the sea like a bath.
- Kusi, the south-east monsoon, runs roughly from May to October. Cooler, drier and noticeably breezier — 29–30 °C by day, and the nights drop to around 21–22 °C in August.
- Masika, the long rains, falls at the changeover from Kaskazi to Kusi: March to May, peaking hard in April.
- Vuli, the short rains, falls at the other changeover: mid-October into December, much lighter and far more scattered.
This is worth getting right because it is commonly stated backwards. Kusi does not bring the rain — Kusi is the dry season. The rain comes in the transitions.
The year in numbers
Averages for Zanzibar: about 1,650 mm of rain a year and roughly 2,920 hours of sunshine, which is a lot of both.
| Month | Rain (mm) | Day (°C) | Sea (°C) | In short |
| January | 85 | 33 | 28.5 | Hot, bright, calm sea |
| February | 55 | 33 | 29 | The driest of the hot months |
| March | 150 | 33 | 29.5 | Warm; rain building late in the month |
| April | 385 | 31 | 29.5 | The wettest month of the year |
| May | 255 | 30 | 28 | Rain easing; the island resets |
| June | 70 | 29 | 27 | Dry season begins; breeze picks up |
| July | 50 | 29 | 26 | Dry, breezy, busy |
| August | 50 | 30 | 25.5 | Coolest nights, around 21 °C |
| September | 50 | 30 | 25.5 | Dry and clear; best air for photography |
| October | 95 | 31 | 26.5 | Warming up; short rains begin late |
| November | 215 | 31 | 28 | Short rains — scattered, not constant |
| December | 185 | 32 | 28.5 | Warm and festive; showers pass quickly |
The sea never drops below about 25 °C. There is no month of the year when you would want a wetsuit.
What "rainy season" actually means here
For most of the year, rain in Zanzibar is not weather that ruins a day — it is a heavy shower that arrives, empties itself, and leaves the air washed and the light extraordinary. November and December average 215 mm and 185 mm respectively, and they are still perfectly good months to be here.
April is different, and we will not pretend otherwise. At 385 mm it holds roughly seven times the rain of February, humidity sits at its annual peak of around 84%, and the rain can settle in for a day rather than an hour. May is the tail of it at 255 mm, easing as the month goes on.
The compensation is real: the island is at its greenest, the coast is close to empty, and prices are at their lowest. Whether that is a good bargain depends entirely on what you came for.
What is specific to this coast
The tide runs your day, not the clock
Michamvi Pingwe is on the east coast, and the tide here is semi-diurnal — two highs and two lows every 24 hours, with the sea withdrawing hundreds of metres at low water. That is not a seasonal thing; it happens every day of the year, and it surprises people more than the weather does. Swimming is best in the two-to-four-hour window around high tide, and the channel between the shore and the sandbank holds water even at low tide.
Swell, and when the sea has an edge
The east coast faces open ocean, so it feels the Kusi breeze more than the north or the west does. Swells run stronger from June to August. It is the same wind that makes those months so comfortable on land.
Seaweed
Seaweed lands on the spring tides, around the full and new moon, and is somewhat more common during Kaskazi — broadly December to March. It is genuinely unpredictable, and no hotel on this coast can promise a beach without it. What helps here is the shape of the shoreline: this is a long open stretch rather than a bay, so the tide carries it back out within days, where a sheltered bay traps it. The beach is cleaned each night.
The best month for a particular thing
- Snorkelling and diving — May to October. The water is calmest and visibility is at its best; mornings beat afternoons, before the wind gets up.
- Whale sharks — October to March, on boat trips rather than from this beach.
- Deep-sea fishing — October to March for the big pelagics; June to September for reef species.
- Photography — June to September. Low humidity and clear air, and the east coast is the sunrise coast: the good light is at 06:00, not in the evening.
- A honeymoon — June to October if you want to be outside all day; January to March if you want heat, calm evenings and the sea at 29 °C.
- Zanzibar plus a safari — June to October matches the dry-season game viewing, when animals gather at water. January to March is the green season, with calving in the Serengeti and far fewer vehicles.
When we are open
Matlai is normally open through March and April, which are quiet, green months on this coast and better than their reputation. We usually close for part of May, when the last of the long rains passes through — the dates are announced in advance rather than fixed, because they depend on how the season actually runs.
So when should you come
If you want the safest possible answer, come in August or September: dry, clear, cool at night, and the best light of the year. If you would rather have heat, a calm sea and the island to yourself, come in February. If you are choosing on price and do not mind an afternoon indoors, March, November and early December are quietly excellent and cost noticeably less.
And if someone has told you Zanzibar is only worth visiting in July and August, they have described one very good month and skipped ten others. More on that in why March and April are the island's best-kept secret.
