If you’re planning a trip to Zanzibar City, you’ll want to get ready for warm, tropical weather that doesn’t really change much during summer. Daytime highs usually hit around 29–33 °C (84–91 °F), and nights rarely slip below 22 °C (72 °F). The Indian Ocean keeps things humid, and the sea is always inviting, with water temperatures hovering near 28 °C (82 °F).
You’ll probably notice that summer mornings often start out clear, but by afternoon, clouds might roll in. There’s a chance of light rain, but it tends to fade as the season moves along.
Sunshine hours don’t really budge, and daylight lasts a little over 12 hours. That gives you plenty of time to be outside.
Wind and humidity shape how the weather feels each day. Breezes from the east and north help take the edge off the heat, but high humidity can make it feel even warmer and more tropical.
This mix of temperature, cloud cover, rain, and wind creates the steady summer climate you’ll find in Zanzibar City.
Overview of Zanzibar City’s Summer Climate
Zanzibar City sits on the west coast of Unguja Island. The city experiences steady warmth, high humidity, and seasonal rains thanks to the Indian Ocean.
Tropical winds, low elevation, and the city’s spot near the equator all work together to create consistent temperatures and a summer season that’s a mix of sunshine and clouds.
Location and Topography
Zanzibar City sits just above sea level, at about 21 meters (69 feet) elevation, according to the Geonames geographical database. The Shuttle Radar Topography Mission (SRTM) also shows the island is mostly flat, with only gentle rises as you head inland.
The city faces west, looking out at the Indian Ocean. This oceanfront spot helps keep summer temperatures from getting out of hand, even when it’s humid.
Unguja is the main island in the Zanzibar Archipelago, which includes Pemba and some smaller islets. Coral reefs and shallow lagoons around the island warm up quickly under the sun, and that extra warmth puts more moisture in the air.
Because the land is so flat, rainwater drains slowly in some spots. Brief flooding can happen during heavy summer showers.
On the bright side, all this humidity helps lush vegetation thrive.
Seasonal Climate Patterns
In summer, you’ll usually see daytime highs from 30–33 °C (86–91 °F). Nights stay warm, too, at 22–25 °C (72–77 °F).
Humidity often climbs above 75%, which makes the air feel heavy. Sea breezes do bring a bit of relief.
Short, intense showers show up more often in early summer. Cloud cover increases as the season goes on, and sometimes skies stay overcast most of the day.
On average, you get 7–9 hours of sunshine daily. That drops a bit during wetter weeks.
The Indian Ocean stays warm, averaging 27–29 °C (81–84 °F). Swimming’s possible any time of year.
Monsoon cycles shift the winds, and in summer, southeast trade winds take over. These winds keep things cooler than you’d find inland.
You end up with a climate that’s warm but not extreme, where reliable warmth mixes with high humidity and some rain.
Comparison to Similar Global Destinations
If you compare Zanzibar’s summer climate to Santiago de Cuba, both have tropical warmth and high humidity. Zanzibar, though, gets steadier sea temperatures and slightly cooler daytime highs.
Santiago often gets hotter inland because there’s less ocean to keep things in check.
Zanzibar’s location near 6° south latitude puts it at the edge of the cyclone belt, so cyclones are rare. That makes the summer climate more predictable than in the Caribbean or South Pacific.
Compared to East African coastal cities like Mombasa, Zanzibar is a bit cooler in summer. Stronger trade winds and the island’s flat landscape with lots of plants help keep temperatures from building up like they do in big coastal cities.
So, if you’re traveling, you’ll get a climate that’s warm, humid, and ocean-influenced, but without the extreme heat or storm risks you might see elsewhere in the tropics.
Summer Temperature Patterns
In Zanzibar City, summer just stays warm and humid. There’s barely any difference between day and night.
You’ll notice steady highs, mild lows, and a consistent dew point that keeps the air muggy.
Average Daily Highs and Lows
During summer, daily high temperatures usually sit at 89°F (32°C). It’s rare for highs to fall under 85°F (29°C) or go over 93°F (34°C).
So, days feel warm but not brutal.
At night, lows hover near 75°F (24°C). After sunset, the air stays humid and heavy.
The dew point hangs around 70–75°F, so nights feel almost as warm as the days.
Unlike other tropical spots, Zanzibar doesn’t really cool off at night. You’ll want light, breathable clothes no matter the hour.
| Time of Day | Average Temp | Comfort Level |
|---|---|---|
| Day High | 89°F / 32°C | Hot & Humid |
| Night Low | 75°F / 24°C | Warm & Muggy |
Hourly Temperature Trends
If you check hourly data, mornings start around 76°F (24°C) and heat up fast. By early afternoon, it’s usually 89–91°F (32–33°C).
Evenings cool a bit, but not much. Midnight temps often stay above 74°F (23°C).
The dew point doesn’t budge much all day, so the air stays muggy whether it’s day or night.
Humidity comfort barely changes, since the dew point records in summer stay steady.
Unlike inland regions where nights cool off, Zanzibar’s coastal setting keeps both air and sea temperatures stable.
If you’re outside, the best times are right after sunrise or around sunset. Midday is usually the toughest, with heat and humidity at their peak.
Hottest and Coolest Summer Days
The hottest stretch comes in mid-February, when highs hit about 91°F (33°C) and lows stay near 76°F (24°C).
Even then, the gap between day and night isn’t big.
The coolest part of summer is early September, with highs closer to 85°F (29°C) and lows around 70°F (21°C).
Even then, the air feels humid, with dew points above 70°F.
This narrow temperature range shows how stable Zanzibar’s weather can be. You don’t get sudden cold snaps or heat waves.
Instead, you get steady warmth, which makes planning your days easier.
Humidity and Comfort Levels
In Zanzibar City, you’ll deal with high humidity all year. There’s barely any seasonal change.
The air often feels heavy, and dew point matters more for comfort than the actual temperature.
Knowing these patterns helps you plan your days and outdoor activities.
Typical Humidity Ranges
Humidity in Zanzibar usually sits above 90% most of the year. You won’t see big swings between dry and wet seasons.
Most days feel muggy or even oppressive. Records show that about 28–31 days each month are like this.
Even in drier months, the air stays moist and heavy.
Being near the equator and the Indian Ocean means there’s constant evaporation. Sea breezes help a bit, but they don’t really get rid of that sticky feeling.
If you don’t like humidity, try to do outdoor stuff in the mornings or evenings, when it’s a little cooler.
Humidity Comfort Index
The humidity comfort index shows how humidity affects your body’s ability to cool off. In Zanzibar, it pretty much always rates as muggy or oppressive.
Sweat evaporates slowly, so you feel warmer than the thermometer says.
For example:
- Muggy (dew point 70°F–74°F): most days
- Oppressive (dew point 75°F–79°F): pretty common during wetter months
- Miserable (dew point 80°F+): happens sometimes, but not too often
So, even if the air temperature is just 83°F, the humidity can make it feel hotter. Lightweight clothes, shade, and lots of water are your best friends.
Dew Point and Its Effects
The dew point really tells you how humid it feels. In Zanzibar, it usually stays above 70°F.
If the dew point climbs to 75°F or higher, you’ll feel sticky, even at night.
That’s why evenings rarely bring the cool relief you might expect in less humid places.
If you’re visiting, don’t count on cooler temps at night for comfort. A night at 72°F can still feel stifling if the dew point is high.
Fans or air conditioning help, and being outdoors feels best when there’s a breeze near the coast.
Rainfall and Precipitation in Summer
During summer in Zanzibar City, rainfall is moderate compared to the wetter months. You’ll get short, regular showers, but the amount and frequency change from June to September.
Monthly Rainfall Totals
Summer rainfall drops compared to the heavy April and May rains. June usually gets about 70–80 mm of precipitation. July comes in close, averaging around 60 mm.
By August, rain drops even more, sometimes just 40–50 mm, making it one of the driest months.
September starts to tick up again, with totals around 30–40 mm. Still, that’s low compared to the “long rains” earlier in the year.
These numbers are averages from weather reports, not exact forecasts. Showers can happen any time, but overall, you’ll get more dry days for outdoor fun.
Wet Days and Rain Frequency
You’ll see a steady but limited number of wet days in summer. June usually brings 7–9 days with measurable rain. July is about the same, with 6–8 wet days.
August often has the fewest, with just 4–6 wet days. September goes up again to 6–7 days, hinting at the upcoming short rainy season.
A “wet day” means more than 0.2 mm of precipitation. Even then, rain usually comes in quick bursts, not all-day storms.
So, you can usually plan around showers, especially if you stick to mornings or late afternoons.
Sliding 31-Day Rainfall Trends
Weather models often use a sliding 31-day period to show how rain changes over the season. If you track it, you’ll see a clear drop from early June into August.
For example:
- Early June: about 75 mm over 31 days
- Mid-July: around 55 mm
- Early August: lowest point, near 45 mm
- Late September: climbing back toward 60 mm
This method smooths out daily ups and downs and highlights the bigger seasonal pattern. It’s handy for spotting the driest stretch, which usually lands in mid-August.
Seasonal Precipitation Patterns
Summer in Zanzibar sits between the long rains of April–May and the short rains of October–November. People often call this the “dry season,” but light showers still show up.
Rainfall is scattered and doesn’t last long, unlike the heavy downpours earlier in the year.
Most rain falls at night or in brief afternoon showers.
Annual precipitation in Zanzibar averages over 1,000 mm, so summer is a real break in the cycle.
That’s why June through September is a popular travel window—rain is low, humidity is manageable, and wet days are predictable without being a hassle.
Cloud Cover and Sunshine
Zanzibar City’s summer months bring a mix of bright skies and periods of heavier cloud cover. Some days feel clear, while others get shaded by thicker clouds.
These shifts change how much time you actually spend in the sun and how warm the afternoons feel.
Cloud Cover Variations
Cloud cover in Zanzibar City shifts with the season. From June to September, skies usually stay clearer than during the wetter months.
You’ll notice plenty of partly cloudy days, so you get steady sunlight but also a break from the direct heat.
In the wetter transition months—like March and April—clouds often take over more of the sky. This means the sunlight gets filtered, and the days look softer and less harsh.
Travelers often find these months better for outdoor activities, though the humidity can still feel pretty high.
Cloud cover changes within a single day, too. Mornings usually start out clearer, but as the day goes on, clouds often build up, especially when sea breezes push moist air inland.
If you’re planning a beach trip or sightseeing, this daily pattern matters.
Overcast and Mostly Cloudy Days
You’ll see fewer overcast days in the dry season, but they pop up more during the long rains in April and May. When it’s mostly cloudy or totally overcast, sunlight diffuses, so the light feels softer and surface temperatures drop.
Even then, the tropical humidity can keep things warm, but without the direct sun, afternoons usually feel more comfortable.
These days often bring short showers or longer stretches of rain, depending on the month. In July and August, overcast skies are rare and most days stay bright.
Still, the occasional cloudy afternoon can sneak in, especially when the winds shift. So, even in the drier months, you’ll want to be ready for both sun and shade.
Hours of Sunlight and Day Length
Zanzibar sits near the equator, so day length stays pretty steady all year. You’ll get about 11.5 to 12.5 hours of daylight each day, with only small changes between June and December.
This makes it easier to plan outdoor activities.
During summer, the solar elevation at midday gets pretty high, putting the sun almost directly overhead. UV exposure is strong, even when it’s partly cloudy.
Honestly, sun protection is a must, whether it’s clear or hazy.
In the drier months from June through September, you can expect 7 to 9 hours of sunshine per day. For cloudier months like April and November, the hours drop—sometimes down to 5 or 6.
This shift really changes the feel of each season and how much natural light you get outside.
Wind and Atmospheric Conditions
In Zanzibar City’s summer, steady ocean breezes and seasonal wind shifts shape the local climate. These conditions impact comfort, air circulation, and the overall experience outdoors.
Wind Speed and Direction
You’ll notice that summer winds here are moderate, not too strong. Average wind speeds usually sit between 12–18 km/h (7–11 mph), which cools the air without making outdoor plans difficult.
Winds mainly come from the south and southeast because of the Indian Ocean’s monsoon system. This airflow helps cut humidity and brings a refreshing feel, especially on the coast.
Since the island is flat, wind speeds stay pretty consistent in most places. You might feel stronger gusts on open beaches compared to more sheltered inland spots.
These breezes also help reduce the heat’s intensity. With moderate summer temperatures, they make walking, sightseeing, and water activities a lot more pleasant.
Seasonal Wind Patterns
In summer, the southeast monsoon—called the Kusi—takes over from June through September, bringing cooler, drier air across the islands.
The Kusi usually blows from the southeast toward the northwest, lining up with the wider Indian Ocean circulation. Its steady flow matters a lot for sailing, fishing, and other maritime activities.
Unlike the wetter months, the summer monsoon doesn’t bring heavy rain. Instead, it helps keep skies clear and stops humidity from building up.
You’ll feel these winds most in the afternoon and early evening. At night, they calm down, so sleeping and indoor time get more comfortable.
Environmental and Geographical Influences
Zanzibar City’s summer weather really shows how coastal geography, vegetation, and city development interact. Temperature, humidity, and rainfall patterns all respond to ocean currents and how people use the land.
Land Cover and Surface Types
The island’s surface is a patchwork of cropland, forested areas, grassland, and built-up land. Cropland and tree cover take up much of Unguja, the main island where Zanzibar City sits.
These land covers actually shape how heat and moisture move through the air. Dense vegetation releases more water vapor through evapotranspiration, which keeps air temperatures lower and bumps up local humidity.
On the other hand, bare soil or sparse vegetation heats up fast under the sun. That can make the ground much hotter during summer.
You’ll probably notice a difference of several degrees when you move from shaded forests to open ground.
Impact of Cropland and Trees
Cropland does a bit of both good and bad for the climate. Fields with crops like rice or cassava hold moisture, which keeps surface heat down.
But after harvest, bare fields soak up more sun and release that heat into the air.
Tree cover, especially in coastal forests and mangroves, gives steady shade and stronger cooling. Trees also block strong sea breezes, which helps keep the soil from drying out and holds local humidity steady.
The mix of cropland and trees even affects rainfall. More trees mean more recycled moisture in the air, which can trigger short, local rain showers.
Heavily farmed areas, though, often get faster runoff during heavy rains, so less water sticks around underground.
Artificial Surfaces and Urban Effects
Artificial surfaces in Zanzibar City—think roads, rooftops, and paved areas—soak up and store a lot more heat than natural land. This creates a mild urban heat island effect, so city nights can feel warmer than the countryside.
Concrete and asphalt don’t let much water in, so rain runs off fast instead of soaking into the ground. That can make flooding worse during the wettest summer months.
Buildings also mess with airflow. Narrow streets and packed housing block breezes, making the city feel warmer and more humid than the coast.
Still, shaded courtyards and tree-lined streets can help cool things down.
The mix of artificial and natural surfaces means you’ll run into microclimates just by walking a few blocks. Heading from the waterfront to the city center, you might feel sudden shifts in temperature, wind, and humidity, all because of different land uses.
Astronomical and Solar Features
During summer in Zanzibar City, the sun’s position and the moon’s cycle both shape the climate and your experience. Solar energy drives daylight, and moon phases change the tides—a big deal for coastal life.
Solar Elevation and Energy
In summer, the sun climbs high in the sky because Zanzibar sits just south of the equator. Around noon, it’s almost straight overhead, making shadows short and sunlight intense.
That high solar elevation gives you long daylight hours, averaging 11.8 to 12 hours per day.
You’ll get steady exposure to high solar energy levels. The UV index often sits between 9 and 10, so if you’re outside for a while, sun protection isn’t optional.
Light clothes, sunscreen, and hats—definitely worth having.
The sea warms up under all that sun, too. Water temperatures usually stay between 25.5°C and 26°C, so swimming and snorkeling stay comfortable.
These sunny conditions make summer a great time for both tourism and local ecosystems to thrive.
| Factor | Summer Value (Approx.) |
|---|---|
| Daylight Hours | 11.8–12.0 hrs |
| UV Index | 9–10 |
| Sea Temperature | 25.5–26°C |
Moon Phases During Summer
The moon runs through its cycle every 29.5 days or so, and in Zanzibar City, you’ll feel its impact on summer coastal life. Full moons light up the nights, which makes evening beach walks or night fishing pretty magical.
Tides follow the moon’s lead. During new and full moons, you’ll see spring tides, when the difference between high and low tide is biggest.
These times expose wide beaches at low tide and bring stronger currents at high tide.
Quarter moons bring neap tides—they’re weaker and more balanced. These calm tides are great for swimming and beginner water sports.
If you keep an eye on the moon phase, you can plan safer and more enjoyable days along Zanzibar’s coast.
Weather Data Sources and Reliability
You get reliable climate info for Zanzibar City from local weather stations, international databases, and reanalysis tools. Each has its own strengths and gaps, so using them together gives you a better sense of summer weather patterns.
Local Meteorological Stations
The most direct weather data comes from Abeid Amani Karume International Airport, just outside Zanzibar City. The airport station tracks daily temperature, rainfall, wind, and humidity.
These readings are valuable because they show the actual conditions you’ll feel on the island. They update often, sometimes several times a day, so you get timely info about short-term changes.
One catch is that the station mainly shows what’s happening near the airport, which might differ a bit from the coast or inland.
Still, for average summer weather, this station gives you a solid baseline.
International Climate Databases
You also have access to big global datasets that gather historical weather records. Sources like the NOAA Global Historical Climatology Network and World Meteorological Organization archives include Zanzibar City.
These databases pull together decades of temperature, rainfall, and sea surface readings. They help you compare Zanzibar’s climate to other places and spot long-term changes.
International datasets can fill gaps if local reports are missing. If the airport weather report skips a day, the global record might fill it in with data from nearby stations or satellites.
The downside? Updates aren’t always instant, so these sources work best for averages, not daily planning.
Reanalysis and Modeling Tools
Reanalysis products like MERRA-2 reanalysis blend meteorological models with observations from satellites, stations, and ships. You end up with a consistent dataset that paints a broader picture of Zanzibar’s summer weather.
These tools reveal things like wind patterns over the Indian Ocean and sea surface temperatures.
Local reports only cover areas with instruments, but reanalysis steps in for the gaps. That’s especially useful when you want to understand bigger influences, such as monsoon winds or ocean currents that affect Zanzibar’s climate.
Of course, the models behind these tools make some assumptions, so they might miss tiny weather details on the island. Still, if you pair reanalysis data with local station info, you get a pretty solid base for climate analysis.