Climate and monthly weather forecast
Zanzibar, Tanzania

Zanzibar, an island located off the coast of Tanzania, is predominantly classified as a tropical monsoon climate in accordance with the Köppen climate classification. The tropical monsoon type, designated as Am on the Köppen scale, is characterized by high temperatures and significant rainfall all year round, which is certainly true for Zanzibar.

On average, the island showcases a high annual temperature range from 28°C (82.4°F) to 33°C (91.4°F), underlining its tropical setting. Meanwhile, rather stable low temperatures are observed, ranging between 22°C (71.6°F) and 25°C (77°F) throughout the year. Such relative consistency in temperature indicates the absence of dramatic seasonal changes, a hallmark of tropical zones.

Zanzibar exhibits a palpable contrast in other climatological aspects, such as rainfall and daylight hours. Rainfall is the most variable, with the precipitation level peaking to an astounding 320mm (12.6") in April. Late fall and winter months, from November into February, also receive considerable amounts of rain. Interestingly, rainfall totals drop dramatically during the mid-year months between June and September, staying below 55mm (2.17"). In terms of daylight, the variance is less pronounced with hours stretching from 11.8 to 12.5 hours throughout the year.

UV index remains consistently high at 9 to 12 all through the year, indicating a constant need to take necessary sun protection measure if enjoying these sunshine-soaked months, with sunshine hours staying consistent at approximately 8 per day. The rush of monsoon rains brings a unique pattern to this island paradise with rains rejuvenating the land in a significant manner.

The best time to visit Zanzibar can be identified by evaluating the balance between advantageous weather conditions and tourist preferences. Consider that, between June and September, rainfall amounts drop to their lowest for the year, falling below 53mm (2.09") and indicating a drier setting. Simultaneously, maximum temperatures are moderate, at approximately 28°C (82.4°F) to 29°C (84.2°F), ensuring a comfortable atmosphere for outdoor exploration. The UV index dips to a slightly lower 9 to 10, therefore reducing the intensity of the sun. Sea temperatures during these months dip slightly but stay above 25.6°C (78.1°F), remaining inviting for beach activity and water sports. Hence, the combination of low rainfall, moderate temperatures, and pleasurable sea temperature establishes the period from June to September as ideal for a visit to Zanzibar.

Conversely, the worst time to visit Zanzibar can be pinpointed during the months of April and May. During this period, the island receives the highest rainfall levels of the year, with an overwhelming 320mm (12.6") and 290mm (11.42") of rain respectively. Such high amounts of rainfall often result in restrictive weather conditions, making outdoor activities less enjoyable. These months also record slightly lower daylight hours, around 12 hours a day, further limiting outdoor exploration opportunities. It is worth noting that, despite such disadvantages, some tourists may still appreciate this time to experience a different facet of the tropical island’s weather patterns.

Between March and May, the spring months in Zanzibar exhibit some of the most variable weather conditions. With maximum temperatures reaching up to 33°C (91.4°F) in March and low temperatures remaining steadily around 25°C (77°F), a warm and humid weather persists. Rainfall patterns shift dramatically during this season, peaking at a significant 320mm (12.6") in April before reducing somewhat to 290mm (11.42") in May. Even with intense rainfall during these months, daylight hours concertedly hover around 12 hours a day allowing plenty of time for activities. Despite the high volumes of rainfall, sea temperatures remain inviting, averaging above 28.3°C (82.9°F) throughout the season, favoring water-based activities.

The summer months of June to August pose a stark contrast to the heavy rainfall of the spring period. Maximum temperatures during this season drop slightly, offering a comfortable range of 28°C (82.4°F) to 28°C (82.4°F), coupled with lowest rainfall figures for the year, between 28mm (1.1") to 53mm (2.09"). The lower temperatures and reduced humidity make this an ideal period for outdoor exploration with less risk of heat fatigue. Generous daylight hours, between 11.8 hours to 11.9 hours, extend the opportunities for sightseeing and activities. With the sea temperature in a tolerable bracket of 25.6°C (78.1°F) to 26°C (78.8°F), swimming and water sports remain a favored activity amongst visitors.

Autumn, from September to November, sees a gradual increase in both temperatures and rainfall. With rain volumes creeping up from 41mm (1.61") in September to 170mm (6.69") in November, visitors may start noticing more rainy days. Despite this, maximum temperatures during this period range from 29°C (84.2°F) to 32°C (89.6°F), presenting a warm setting. Daylight hours subtly increase, sitting between 12.1 to 12.4 hours a day, providing ample time for both indoor and outdoor activities. Sea temperatures rebound from the summer lows, gradually warming from 25.9°C (78.6°F) in September to 27.9°C (82.2°F) towards end-November, amplifying the appeal of beach activities and water sports.

Winter in Zanzibar, encompassing December to February, is characterized by high temperatures and abundant rainfall. The maximum temperature hovers consistently around 32°C (89.6°F) - a reminder of Zanzibar's tropical climate. Rainfall is also prominent, with December to February witnessing downpours of 140mm (5.51") to 170mm (6.69") on average. Yet, the daylight hours stay steady at 12.4 to 12.5 hours, ensuring that tourists can make the most of their holidays despite the rain. Sea temperatures peak at 28.4°C (83.1°F), inviting swimmers to take a dip even in winter months. Winter thus provides a distinct experience, differentiating it from summer and establishing it as a season for those seeking a tropical winter escape.

Kicking off the year, the Zanzibar weather in January offers warmth with high temperatures peaking at 32°C (89.6°F) and low temperatures hardly dipping below 24°C (75.2°F). The relatively clear skies permit an impressive 12.4 hours of daylight, out of which eight hours are often filled with brilliant sunshine. Weather in January »

Following a fairly dry January, February appears to continue this pattern with slightly increased rainfall as compared to the previous month. Temperatures remain consistently warm, similar to January, affirming the area's equatorial setting. Weather in February »

In March, Zanzibar's weather turns a bit moody as the rainfall escalates substantially, showing the onset of the long rainy season. Compared to February, there are more rainy days; however, this does not severely affect the temperature patterns. Weather in March »

The month of April sees the peak of the long rainy season in Zanzibar. During this month, Zanzibar receives maximum rainfall, a considerable jump from the figures observed in March. Contrary to what might be expected, temperatures do not plummet drastically but rather cool off a bit leading to comfortable weather for most of the time. Weather in April »

May marks the retreat of the long rainy season with a gradual decrease in rainfall levels and rainy days from the excessive showers seen in April. The temperatures display a modest decline, making the weather slightly more relaxed. Weather in May »

June is the onset of the dry season in Zanzibar, marked by a substantial reduction in rainfall to merely 53mm (2.09") spread across seven days. With the mild, relieved temperatures, June becomes one of the most comfortable months to witness Zanzibar's tropical charm. Weather in June »

July reiterates the calm and dry attributes of the previous month's weather, only with slightly cooler temperatures. Minimal changes are noticed concerning daylight, sunshine, and UV index values from June to July. This consistency helps maintain a predictable weather pattern, still holding the rain at bay. Weather in July »

As Zanzibar moves further into the dry season, August continues to boast of relatively dry days and balmier temperatures. The weather yields subtle differences when compared with July. Total daylight hours start increasing again, and the sunshine maintains its uniform stretch. Weather in August »

September in Zanzibar reflects heightened dry conditions with rainfall levels dropping further to just 41mm (1.61"). Conceivably the most pleasant month, September is also noted for its slightly increased day length and maintaining the high sunshine levels. Weather in September »

Moving on to October, the weather in Zanzibar undergoes little variation from September. Though rainfall levels and temperatures show a marginal increase, this does not disrupt the overall calm atmosphere. The daylight hours persist in their moderate fluctuation while sunshine remains at a steady high. Weather in October »

In November, Zanzibar prepares for the short rainy season. A substantial leap from October's figures brings considerable rainfall this month. Nonetheless, the temperatures climb, maintaining the amiable weather and compensating for any dampened spirits. Weather in November »

Closing the year, Zanzibar's weather in December combines a slight drop in rainfall consolidating the end of the short rains. However, the temperatures continue to soar, bringing back the tropical warmth that caters to holidaymakers from cooler regions. Weather in December »