Climate in Zanzibar

In Zanzibar, the climate is tropical, hot all year round, with a hotter period from December to March, and a relatively cool period from May to August. There are two rainy seasons: one more intense, known as the "long rains" season, from March to May, with the peak in April, and the other less intense, known as the "short rains" season, between mid-October and December.
Zanzibar is an archipelago formed by two main islands, Unguja (also called Zanzibar) and Pemba, plus several smaller islands. It is a semi-autonomous region of Tanzania, a great African country just south of the Equator.

The climate in detail

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• Climate data
• Sea temperature
• Cyclones
• Weather by month
• When to go
• What to pack

Climate data

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As mentioned, temperatures are high throughout the year. The hottest period is from December to March, during which the maximum temperature hovers around 32/33 degrees Celsius (90/91 °F) and the humidity is high, although the breeze tempers a little the heat. In the worst moments, the temperature can reach 36/38 °C (97/100 °F).
The period from May to August, when the trade winds predominate, blowing moderate from the southeast, is cooler, with highs around 29/30 °C (84/86 °F).

Total annual rainfall is about 1,650 millimeters (65 inches) in Zanzibar and 1,900 mm (75 in) in Pemba. April and May are the wettest months, when downpours can be really strong and cause floods. However, some short thunderstorms can occur throughout the year.

The amount of sunshine in Zanzibar is good enough all year round, except in the long rains season, from March to May, where cloudiness and downpours can last a little longer.

Sea temperature

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The sea in Zanzibar is always warm enough for swimming: the water temperature ranges from 25.5 °C (78 °F) in August and September to 28.5/29.5 °C (83/85 °F) between December and April.

Tropical cyclones

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The archipelago is located near the Equator (Zanzibar is at 6 degrees south latitude and Pemba at 5 degrees), at the limit of the area where tropical cyclones can form. In fact, Zanzibar is hardly ever affected by cyclones, probably also because of the prevailing currents, however, it can not be excluded that a cyclone of the Southern Hemisphere may pass (over the ocean to the east) close enough to cause storm surges. This can happen from November to mid-May, but especially from late December to mid-April.
However, according to the reports of that time, on April 15, 1872, the archipelago was hit at full force by a cyclone.

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Zanzibar - Weather by month

Based on the period 1991-2020
(January - February - March - April - May - June - July - August - September - October - November - December)

In January, the average temperature is of 28,8 °C (84 °F), with a minimum of 24,7 °C (76,5 °F) and a maximum of 32,8 °C (91 °F).
On the coldest nights of the month, the temperature usually drops to around 21 °C (69,5 °F).
On the warmest days of the month, the temperature usually reaches around 35 °C (94,5 °F).
Precipitation amounts to 85 mm (3,3 in), distributed over 10 days.
On average, there are 275 hours of sunshine per month, i.e. 9 hours per day.
The average humidity is 75%.
The average wind speed is 14 kph (8 kph).
The average sea temperature is of 28,5 °C (83,5 °F).

In February, the warmest month of the year, the average temperature is of 28,8 °C (84 °F), with a minimum of 24,5 °C (76,2 °F) and a maximum of 33,1 °C (91,6 °F).
On the coldest nights of the month, the temperature usually drops to around 21,5 °C (71 °F).
On the warmest days of the month, the temperature usually reaches around 35,5 °C (96 °F).
Precipitation amounts to 55 mm (2,2 in), distributed over 7 days.
On average, there are 245 hours of sunshine per month, i.e. 9 hours per day.
The average humidity is 75%.
The average wind speed is 12 kph (7 kph).
The average sea temperature is of 29 °C (84 °F).

In March, the average temperature is of 28,8 °C (84 °F), with a minimum of 24,8 °C (76,6 °F) and a maximum of 32,8 °C (91 °F).
On the coldest nights of the month, the temperature usually drops to around 22 °C (72 °F).
On the warmest days of the month, the temperature usually reaches around 35,5 °C (96 °F).
Precipitation amounts to 150 mm (5,9 in), distributed over 13 days.
On average, there are 230 hours of sunshine per month, i.e. 7,5 hours per day.
The average humidity is 79%.
The average wind speed is 10 kph (6 kph).
The average sea temperature is of 29,5 °C (85 °F).

In April, the average temperature is of 27,8 °C (82 °F), with a minimum of 24,7 °C (76,5 °F) and a maximum of 30,8 °C (87,5 °F).
On the coldest nights of the month, the temperature usually drops to around 22,5 °C (72,5 °F).
On the warmest days of the month, the temperature usually reaches around 33,5 °C (92 °F).
Precipitation amounts to 385 mm (15,2 in), distributed over 18 days.
On average, there are 185 hours of sunshine per month, i.e. 6 hours per day.
The average humidity is 84%.
The average wind speed is 11 kph (7 kph).
The average sea temperature is of 29,5 °C (84,5 °F).

In May, the average temperature is of 26,9 °C (80 °F), with a minimum of 24 °C (75,2 °F) and a maximum of 29,9 °C (85,8 °F).
On the coldest nights of the month, the temperature usually drops to around 21 °C (69,5 °F).
On the warmest days of the month, the temperature usually reaches around 32 °C (89,5 °F).
Precipitation amounts to 255 mm (10 in), distributed over 15 days.
On average, there are 210 hours of sunshine per month, i.e. 6,5 hours per day.
The average humidity is 82%.
The average wind speed is 14 kph (9 kph).
The average sea temperature is of 28 °C (82,5 °F).

In June, the average temperature is of 26,3 °C (79 °F), with a minimum of 23,2 °C (73,7 °F) and a maximum of 29,4 °C (85 °F).
On the coldest nights of the month, the temperature usually drops to around 20,5 °C (69 °F).
On the warmest days of the month, the temperature usually reaches around 31 °C (88 °F).
Precipitation amounts to 70 mm (2,8 in), distributed over 7 days.
On average, there are 240 hours of sunshine per month, i.e. 8 hours per day.
The average humidity is 78%.
The average wind speed is 15 kph (10 kph).
The average sea temperature is of 27 °C (80,5 °F).

In July, the average temperature is of 25,7 °C (78 °F), with a minimum of 22,3 °C (72,2 °F) and a maximum of 29,1 °C (84,4 °F).
On the coldest nights of the month, the temperature usually drops to around 19,5 °C (67 °F).
On the warmest days of the month, the temperature usually reaches around 30,5 °C (87 °F).
Precipitation amounts to 50 mm (2 in), distributed over 8 days.
On average, there are 250 hours of sunshine per month, i.e. 8 hours per day.
The average humidity is 75%.
The average wind speed is 16 kph (10 kph).
The average sea temperature is of 26 °C (78,5 °F).

In August, the coldest month of the year, the average temperature is of 25,6 °C (78 °F), with a minimum of 21,6 °C (70,9 °F) and a maximum of 29,5 °C (85,1 °F).
On the coldest nights of the month, the temperature usually drops to around 19 °C (66 °F).
On the warmest days of the month, the temperature usually reaches around 31 °C (88 °F).
Precipitation amounts to 50 mm (2 in), distributed over 8 days.
On average, there are 250 hours of sunshine per month, i.e. 8 hours per day.
The average humidity is 75%.
The average wind speed is 13 kph (8 kph).
The average sea temperature is of 25,5 °C (77,5 °F).

In September, the average temperature is of 25,9 °C (79 °F), with a minimum of 21,3 °C (70,4 °F) and a maximum of 30,4 °C (86,7 °F).
On the coldest nights of the month, the temperature usually drops to around 18 °C (64 °F).
On the warmest days of the month, the temperature usually reaches around 32 °C (90 °F).
Precipitation amounts to 50 mm (2 in), distributed over 8 days.
On average, there are 255 hours of sunshine per month, i.e. 8,5 hours per day.
The average humidity is 75%.
The average wind speed is 13 kph (8 kph).
The average sea temperature is of 25,5 °C (78,5 °F).

In October, the average temperature is of 26,8 °C (80 °F), with a minimum of 22,5 °C (72,4 °F) and a maximum of 31 °C (87,9 °F).
On the coldest nights of the month, the temperature usually drops to around 20 °C (67,5 °F).
On the warmest days of the month, the temperature usually reaches around 33 °C (91,5 °F).
Precipitation amounts to 95 mm (3,7 in), distributed over 9 days.
On average, there are 275 hours of sunshine per month, i.e. 9 hours per day.
The average humidity is 78%.
The average wind speed is 13 kph (8 kph).
The average sea temperature is of 26,5 °C (79,5 °F).

In November, the average temperature is of 27,2 °C (81 °F), with a minimum of 23,5 °C (74,2 °F) and a maximum of 31 °C (87,7 °F).
On the coldest nights of the month, the temperature usually drops to around 20,5 °C (68,5 °F).
On the warmest days of the month, the temperature usually reaches around 33,5 °C (92 °F).
Precipitation amounts to 215 mm (8,5 in), distributed over 11 days.
On average, there are 250 hours of sunshine per month, i.e. 8,5 hours per day.
The average humidity is 82%.
The average wind speed is 9 kph (6 kph).
The average sea temperature is of 28 °C (82 °F).

In December, the average temperature is of 28,2 °C (83 °F), with a minimum of 24,4 °C (75,8 °F) and a maximum of 32 °C (89,6 °F).
On the coldest nights of the month, the temperature usually drops to around 20,5 °C (69,5 °F).
On the warmest days of the month, the temperature usually reaches around 34,5 °C (94 °F).
Precipitation amounts to 185 mm (7,3 in), distributed over 13 days.
On average, there are 260 hours of sunshine per month, i.e. 8,5 hours per day.
The average humidity is 80%.
The average wind speed is 11 kph (7 kph).
The average sea temperature is of 28,5 °C (83,5 °F).

When to go

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The best months to enjoy the sun and the sea of Zanzibar are July, August and September.
In Zanzibar, the rains cease or drastically decrease already in June, so on this island, you can also go in June, while on the more northern island of Pemba, it still rains a bit in this month.
If you want, you can also choose the months of January and February, between the two rainy seasons, though this period is hot and sultry.

What to pack

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In winter (June to August): pack light clothes, a sweatshirt for the evening, a light scarf for the breeze, and sunscreen. When going to the reef, you can bring snorkeling equipment, including water shoes or rubber-soled shoes.
In summer (December to February): pack tropics-friendly, loose-fitting clothing, a light sweatshirt for the evening, a light raincoat or umbrella in December, and sunscreen. When going to the reef, you can bring snorkeling equipment, including water shoes or rubber-soled shoes.

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