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Average Weather in Zanzibar Tanzania

In Zanzibar, the wet season is hot and mostly cloudy; the dry season is warm, windy, and mostly clear; and it is oppressive year round. Over the course of the year, the temperature typically varies from 70°F to 91°F and is rarely below 67°F or above 93°F.

Based on the beach/pool score, the best time of year to visit Zanzibar for hot-weather activities is from early June to early October.

Climate Summary

hotwarmhotJanFebMarAprMayJunJulAugSepOctNovDecNowNow79%79%27%27%clearovercastprecipitation: 6.8 inprecipitation: 6.8 in0.3 in0.3 inmuggy: 100%muggy: 100%91%91%beach/pool score: 8.4beach/pool score: 8.44.44.4
Click on each chart for more information.

Temperature

The temperature in Zanzibar varies so little throughout the year that it is not entirely meaningful to discuss hot and cold seasons.

Average High and Low Temperature

Average High and Low Temperature in ZanzibarJanFebMarAprMayJunJulAugSepOctNovDec0°F0°F10°F10°F20°F20°F30°F30°F40°F40°F50°F50°F60°F60°F70°F70°F80°F80°F90°F90°F100°F100°FSep 285°FSep 285°FFeb 1691°FFeb 1691°F70°F70°F76°F76°FJan 189°FJan 189°FMay 2585°FMay 2585°F76°F76°F76°F76°F75°F75°FNowNow
The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.

The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.

Average Hourly Temperature

Average Hourly Temperature in ZanzibarJanFebMarAprMayJunJulAugSepOctNovDec12 AM12 AM4 AM4 AM8 AM8 AM12 PM12 PM4 PM4 PM8 PM8 PM12 AM12 AMNowNowcomfortablewarmhothotcomfortable
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The average hourly temperature, color coded into bands. The shaded overlays indicate night and civil twilight.

Santiago de Cuba, Cuba (7,995 miles away); Brenas, Puerto Rico (7,377 miles); and Itaparica, Brazil (5,316 miles) are the far-away foreign places with temperatures most similar to Zanzibar (view comparison).

Clouds

In Zanzibar, the average percentage of the sky covered by clouds experiences extreme seasonal variation over the course of the year.

The clearer part of the year in Zanzibar begins around May 11 and lasts for 6.1 months, ending around November 16. On September 1, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 79% of the time, and overcast or mostly cloudy 21% of the time.

The cloudier part of the year begins around November 16 and lasts for 5.9 months, ending around May 11. On March 15, the cloudiest day of the year, the sky is overcast or mostly cloudy 73% of the time, and clear, mostly clear, or partly cloudy 27% of the time.

Cloud Cover Categories

Cloud Cover Categories in ZanzibarclearercloudiercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Sep 179%Sep 179%Mar 1527%Mar 1527%May 1152%May 1152%Nov 1653%Nov 1653%NowNowclearmostly clearpartly cloudymostly cloudyovercast
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds.

Precipitation

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Zanzibar varies very significantly throughout the year.

The wetter season lasts 6.2 months, from November 17 to May 22, with a greater than 34% chance of a given day being a wet day. The chance of a wet day peaks at 64% on April 20.

The drier season lasts 5.8 months, from May 22 to November 17. The smallest chance of a wet day is 4% on July 19.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 64% on April 20.

Daily Chance of Precipitation

Daily Chance of Precipitation in ZanzibarwetwetdryJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%Apr 2064%Apr 2064%Jul 194%Jul 194%Jan 130%Jan 130%Nov 1734%Nov 1734%May 2234%May 2234%rain
The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).

Rainfall

To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. Zanzibar experiences extreme seasonal variation in monthly rainfall.

The rainy period of the year lasts for 9.5 months, from September 24 to July 6, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around April 22, with an average total accumulation of 6.8 inches.

The rainless period of the year lasts for 2.6 months, from July 6 to September 24. The least rain falls around August 29, with an average total accumulation of 0.3 inches.

Average Monthly Rainfall

Average Monthly Rainfall in ZanzibarrainrainJanFebMarAprMayJunJulAugSepOctNovDec0 in0 in2 in2 in4 in4 in6 in6 in8 in8 in10 in10 in12 in12 inApr 226.8 inApr 226.8 inAug 290.3 inAug 290.3 inNov 302.7 inNov 302.7 inJan 281.6 inJan 281.6 inJul 60.5 inJul 60.5 in
The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average liquid-equivalent snowfall.

Sun

The length of the day in Zanzibar does not vary substantially over the course of the year, staying within 29 minutes of 12 hours throughout. In 2021, the shortest day is June 21, with 11 hours, 46 minutes of daylight; the longest day is December 21, with 12 hours, 29 minutes of daylight.

Hours of Daylight and Twilight

Hours of Daylight and Twilight in ZanzibarJanFebMarAprMayJunJulAugSepOctNovDec0 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hr12 hr, 6 minSep 2212 hr, 6 minSep 2212 hr, 29 minDec 2112 hr, 29 minDec 2112 hr, 7 minMar 2012 hr, 7 minMar 2011 hr, 46 minJun 2111 hr, 46 minJun 21daydaynightNowNow
The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.

The earliest sunrise is at 5:55 AM on November 12, and the latest sunrise is 39 minutes later at 6:35 AM on July 17. The earliest sunset is at 6:14 PM on May 23, and the latest sunset is 34 minutes later at 6:47 PM on February 1.

Daylight saving time (DST) is not observed in Zanzibar during 2021.

Sunrise & Sunset with Twilight

Sunrise & Sunset with Twilight in ZanzibarJanFebMarAprMayJunJulAugSepOctNovDec2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMNov 125:55 AMNov 125:55 AM6:47 PMFeb 16:47 PMFeb 1May 236:14 PMMay 236:14 PM6:35 AMJul 176:35 AMJul 17daynightSolarMidnightSolarMidnightSolarNoonSunriseSunsetNowNow
The solar day over the course of the year 2021. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray.

Moon

The figure below presents a compact representation of key lunar data for 2021. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases.

Moon Rise, Set & Phases

The time in which the moon is above the horizon (light blue area), with new moons (dark gray lines) and full moons (blue lines) indicated. The shaded overlays indicate night and civil twilight.

Humidity

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

The perceived humidity level in Zanzibar, as measured by the percentage of time in which the humidity comfort level is muggy, oppressive, or miserable, does not vary significantly over the course of the year, staying within 4% of 96% throughout.

Humidity Comfort Levels

Humidity Comfort Levels in ZanzibarJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%Aug 1491%Aug 1491%100%Mar 23100%Mar 23NowNowmiserablemiserableoppressiveoppressivemuggymuggyhumidhumid
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
The percentage of time spent at various humidity comfort levels, categorized by dew point.

Wind

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed in Zanzibar experiences significant seasonal variation over the course of the year.

The windier part of the year lasts for 5.6 months, from April 24 to October 10, with average wind speeds of more than 11.2 miles per hour. The windiest day of the year is July 4, with an average hourly wind speed of 14.3 miles per hour.

The calmer time of year lasts for 6.4 months, from October 10 to April 24. The calmest day of the year is March 25, with an average hourly wind speed of 8.0 miles per hour.

Average Wind Speed

Average Wind Speed in ZanzibarwindyJanFebMarAprMayJunJulAugSepOctNovDec0 mph0 mph2 mph2 mph4 mph4 mph6 mph6 mph8 mph8 mph10 mph10 mph12 mph12 mph14 mph14 mph16 mph16 mphJul 414.3 mphJul 414.3 mphMar 258.0 mphMar 258.0 mphApr 2411.2 mphApr 2411.2 mphOct 1011.2 mphOct 1011.2 mphNowNow
The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The predominant average hourly wind direction in Zanzibar varies throughout the year.

The wind is most often from the east for 1.6 months, from February 20 to April 7 and for 3.7 months, from August 29 to December 21, with a peak percentage of 90% on November 6. The wind is most often from the south for 4.7 months, from April 7 to August 29, with a peak percentage of 95% on June 17. The wind is most often from the north for 2.0 months, from December 21 to February 20, with a peak percentage of 60% on January 1.

Wind Direction

Wind Direction in ZanzibarNESENJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%NowNowsoutheastnorth
northeastsouthwest
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions, excluding hours in which the mean wind speed is less than 1.0 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Water Temperature

Zanzibar is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.

The average water temperature experiences some seasonal variation over the course of the year.

The time of year with warmer water lasts for 2.4 months, from February 16 to April 27, with an average temperature above 83°F. The day of the year with the warmest water is March 25, with an average temperature of 85°F.

The time of year with cooler water lasts for 3.0 months, from July 3 to October 5, with an average temperature below 79°F. The day of the year with the coolest water is August 14, with an average temperature of 78°F.

Average Water Temperature

The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.

Best Time of Year to Visit

To characterize how pleasant the weather is in Zanzibar throughout the year, we compute two travel scores.

The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best time of year to visit Zanzibar for general outdoor tourist activities is from late June to mid September, with a peak score in the second week of August.

Tourism Score

Tourism Score in Zanzibarbest timeJanFebMarAprMayJunJulAugSepOctNovDec002244668810107.57.52.82.8NowNowprecipitationprecipitationcloudsclouds tourism score
The tourism score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Zanzibar for hot-weather activities is from early June to early October, with a peak score in the last week of August.

Beach/Pool Score

Beach/Pool Score in Zanzibarbest timeJanFebMarAprMayJunJulAugSepOctNovDec002244668810108.48.44.44.4NowNowprecipitationprecipitationtemperaturetemperature beach/pool score
The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

Methodology

For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.

Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.

Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.

Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.

Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.

Growing Season

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

Temperatures in Zanzibar are sufficiently warm year round that it is not entirely meaningful to discuss the growing season in these terms. We nevertheless include the chart below as an illustration of the distribution of temperatures experienced throughout the year.

Time Spent in Various Temperature Bands and the Growing Season

Time Spent in Various Temperature Bands and the Growing Season in ZanzibarJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%100%Jan 1100%Jan 1100%Jul 3100%Jul 3NowNowcomfortablewarmhot
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The percentage of time spent in various temperature bands. The black line is the percentage chance that a given day is within the growing season.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.

Growing Degree Days

Growing Degree Days in ZanzibarJanFebMarAprMayJunJulAugSepOctNovDec0°F0°F2,000°F2,000°F4,000°F4,000°F6,000°F6,000°F8,000°F8,000°F10,000°F10,000°FJul 490°FJul 490°FAug 4900°FAug 4900°FJun 3010,706°FJun 3010,706°FNowNow
The average growing degree days accumulated over the course of the year, with 25th to 75th and 10th to 90th percentile bands.

Solar Energy

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

The average daily incident shortwave solar energy experiences some seasonal variation over the course of the year.

The brighter period of the year lasts for 2.2 months, from September 7 to November 12, with an average daily incident shortwave energy per square meter above 6.9 kWh. The brightest day of the year is October 10, with an average of 7.3 kWh.

The darker period of the year lasts for 2.2 months, from March 11 to May 19, with an average daily incident shortwave energy per square meter below 5.7 kWh. The darkest day of the year is April 6, with an average of 5.3 kWh.

Average Daily Incident Shortwave Solar Energy

Average Daily Incident Shortwave Solar Energy in ZanzibarbrightdarkJanFebMarAprMayJunJulAugSepOctNovDec0 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWh8 kWh8 kWhOct 107.3 kWhOct 107.3 kWhApr 65.3 kWhApr 65.3 kWhMay 195.7 kWhMay 195.7 kWhNowNow
The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

Topography

For the purposes of this report, the geographical coordinates of Zanzibar are -6.164 deg latitude, 39.198 deg longitude, and 46 ft elevation.

The topography within 2 miles of Zanzibar contains only modest variations in elevation, with a maximum elevation change of 144 feet and an average elevation above sea level of 27 feet. Within 10 miles also contains only modest variations in elevation (440 feet). Within 50 miles contains only modest variations in elevation (1,171 feet).

The area within 2 miles of Zanzibar is covered by artificial surfaces (44%), water (44%), and cropland (11%), within 10 miles by water (56%) and cropland (29%), and within 50 miles by water (63%) and trees (13%).

Data Sources

This report illustrates the typical weather in Zanzibar, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.

Temperature and Dew Point

There is only a single weather station, Abeid Amani Karume International Airport, in our network suitable to be used as a proxy for the historical temperature and dew point records of Zanzibar.

At a distance of 7 kilometers from Zanzibar, closer than our threshold of 150 kilometers, this station is deemed sufficiently nearby to be relied upon as our primary source for temperature and dew point records.

The station records are corrected for the elevation difference between the station and Zanzibar according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.

Please note that the station records themselves may additionally have been back-filled using other nearby stations or the MERRA-2 reanalysis.

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Algorithms 2nd Edition , by Jean Meeus.

All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.

Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.

Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.

Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .

Time zones for airports and weather stations are provided by AskGeo.com .

Maps are © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.

Disclaimer

The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.

We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.

We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.