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Climate and Average Weather Year Round at Diego Garcia British Indian Ocean Territory

The climate at Diego Garcia is hot, oppressive, windy, and overcast. Over the course of the year, the temperature typically varies from 76°F to 88°F and is rarely below 74°F or above 91°F.

Based on the beach/pool score, the best time of year to visit Diego Garcia for hot-weather activities is from late May to early September.

Climate at Diego Garcia

hotwarmhotJanFebMarAprMayJunJulAugSepOctNovDecNowNow38%38%21%21%overcastprecipitation: 11.1 inprecipitation: 11.1 in2.7 in2.7 inmuggy: 100%muggy: 100%97%97%beach/pool score: 6.5beach/pool score: 6.53.93.9
Diego Garcia weather by month. Click on each chart for more information.

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

Average High and Low Temperature at Diego Garcia

Average High and Low Temperature at Diego GarciaJanFebMarAprMayJunJulAugSepOctNovDec0°F0°F10°F10°F20°F20°F30°F30°F40°F40°F50°F50°F60°F60°F70°F70°F80°F80°F90°F90°F100°F100°FAug 1084°FAug 1084°FMar 2488°FMar 2488°F76°F76°F79°F79°FMay 187°FMay 187°FJun 2685°FJun 2685°FSep 2585°FSep 2585°F79°F79°F79°F79°F77°F77°F77°F77°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.
AverageJanFebMarAprMayJunJulAugSepOctNovDec
High 86°F87°F88°F88°F87°F85°F84°F84°F84°F85°F87°F87°F
Temp. 82°F82°F83°F83°F82°F81°F80°F80°F80°F81°F82°F82°F
Low 78°F78°F79°F79°F79°F78°F77°F77°F77°F77°F78°F78°F

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 at Diego Garcia

Average Hourly Temperature at Diego GarciaJanFebMarAprMayJunJulAugSepOctNovDec12 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AMNowNowwarmhothot
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.

Mata-Utu, Wallis & Futuna (7,530 miles away); Fagatogo, American Samoa (7,871 miles); and Chichiriviche, Venezuela (9,756 miles) are the far-away foreign places with temperatures most similar to Diego Garcia (view comparison).

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At Diego Garcia, the average percentage of the sky covered by clouds experiences mild seasonal variation over the course of the year.

The clearer part of the year at Diego Garcia begins around April 2 and lasts for 6.1 months, ending around October 7.

The clearest month of the year at Diego Garcia is July, during which on average the sky is clear, mostly clear, or partly cloudy 37% of the time.

The cloudier part of the year begins around October 7 and lasts for 5.9 months, ending around April 2.

The cloudiest month of the year at Diego Garcia is January, during which on average the sky is overcast or mostly cloudy 79% of the time.

Cloud Cover Categories at Diego Garcia

Cloud Cover Categories at Diego GarciaclearercloudiercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Jul 2938%Jul 2938%Jan 1021%Jan 1021%Apr 229%Apr 229%Oct 730%Oct 730%NowNowmostly clearpartly cloudymostly cloudyovercastclear
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.
FractionJanFebMarAprMayJunJulAugSepOctNovDec
Cloudier 79%77%72%69%65%65%63%64%68%71%71%74%
Clearer 21%23%28%31%35%35%37%36%32%29%29%26%

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

The wetter season lasts 6.1 months, from September 19 to March 24, with a greater than 49% chance of a given day being a wet day. The month with the most wet days at Diego Garcia is January, with an average of 21.1 days with at least 0.04 inches of precipitation.

The drier season lasts 5.9 months, from March 24 to September 19. The month with the fewest wet days at Diego Garcia is July, with an average of 9.7 days with at least 0.04 inches of precipitation.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. The month with the most days of rain alone at Diego Garcia is January, with an average of 21.1 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 70% on January 21.

Daily Chance of Precipitation at Diego Garcia

Daily Chance of Precipitation at Diego GarciawetwetdryJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%Jan 2170%Jan 2170%Jul 3028%Jul 3028%Sep 1949%Sep 1949%Mar 2449%Mar 2449%NowNowrain
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).
Days ofJanFebMarAprMayJunJulAugSepOctNovDec
Rain 21.1d17.8d15.5d13.3d11.3d10.1d9.7d10.5d14.2d17.3d16.2d18.1d

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. Diego Garcia experiences extreme seasonal variation in monthly rainfall.

Rain falls throughout the year at Diego Garcia. The month with the most rain at Diego Garcia is January, with an average rainfall of 11.1 inches.

The month with the least rain at Diego Garcia is July, with an average rainfall of 3.0 inches.

Average Monthly Rainfall at Diego Garcia

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 snowfall.
JanFebMarAprMayJunJulAugSepOctNovDec
Rainfall 11.1″8.5″5.7″5.0″4.1″3.2″3.0″3.1″6.0″7.4″7.1″7.8″

The length of the day at Diego Garcia does not vary substantially over the course of the year, staying within 33 minutes of 12 hours throughout. In 2024, the shortest day is June 21, with 11 hours, 42 minutes of daylight; the longest day is December 21, with 12 hours, 33 minutes of daylight.

Hours of Daylight and Twilight at Diego Garcia

Hours of Daylight and Twilight at Diego GarciaJanFebMarAprMayJunJulAugSepOctNovDec0 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hr12 hr, 6 minSep 2212 hr, 6 minSep 2212 hr, 33 minDec 2112 hr, 33 minDec 2112 hr, 7 minMar 2012 hr, 7 minMar 2011 hr, 42 minJun 2111 hr, 42 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.
Hours ofJanFebMarAprMayJunJulAugSepOctNovDec
Daylight 12.5h12.3h12.1h11.9h11.8h11.7h11.7h11.9h12.1h12.3h12.4h12.5h

The earliest sunrise is at 6:41 AM on November 14, and the latest sunrise is 43 minutes later at 7:24 AM on July 16. The earliest sunset is at 6:59 PM on May 24, and the latest sunset is 37 minutes later at 7:36 PM on January 30.

Daylight saving time (DST) is not observed at Diego Garcia during 2024.

Sunrise & Sunset with Twilight at Diego Garcia

Sunrise & Sunset with Twilight at Diego GarciaJanFebMarAprMayJunJulAugSepOctNovDec2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMNov 146:41 AMNov 146:41 AM7:36 PMJan 307:36 PMJan 30May 246:59 PMMay 246:59 PM7:24 AMJul 167:24 AMJul 16daynightSolarMidnightSolarMidnightSolarNoonSunriseSunsetNowNow
The solar day over the course of the year 2024. 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.

The figure below presents a compact representation of the sun's elevation (the angle of the sun above the horizon) and azimuth (its compass bearing) for every hour of every day in the reporting period. The horizontal axis is the day of the year and the vertical axis is the hour of the day. For a given day and hour of that day, the background color indicates the azimuth of the sun at that moment. The black isolines are contours of constant solar elevation.

Solar Elevation and Azimuth at Diego Garcia

Solar Elevation and Azimuth at Diego GarciaJanFebMarAprMayJunJulAugSepOctNovDec12 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AM000010101010202020203030303040404040505050506060606070707080000010101010202020203030303040404040505050506060607070805990NowNow
northeastsouthwest
Solar elevation and azimuth over the course of the year 2024. The black lines are lines of constant solar elevation (the angle of the sun above the horizon, in degrees). The background color fills indicate the azimuth (the compass bearing) of the sun. The lightly tinted areas at the boundaries of the cardinal compass points indicate the implied intermediate directions (northeast, southeast, southwest, and northwest).

The figure below presents a compact representation of key lunar data for 2024. 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 at Diego Garcia

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.

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 at Diego Garcia, 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 2% of 98% throughout.

Humidity Comfort Levels at Diego Garcia

Humidity Comfort Levels at Diego GarciaJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%Jul 3097%Jul 3097%100%Nov 23100%Nov 23NowNowmiserablemiserableoppressiveoppressivemuggymuggy
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.
JanFebMarAprMayJunJulAugSepOctNovDec
Muggy days 31.0d29.0d31.0d29.9d30.7d29.4d30.1d30.0d29.1d30.8d30.0d31.0d

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 at Diego Garcia experiences extreme seasonal variation over the course of the year.

The windier part of the year lasts for 5.0 months, from May 22 to October 22, with average wind speeds of more than 13.1 miles per hour. The windiest month of the year at Diego Garcia is August, with an average hourly wind speed of 17.5 miles per hour.

The calmer time of year lasts for 7.0 months, from October 22 to May 22. The calmest month of the year at Diego Garcia is March, with an average hourly wind speed of 9.0 miles per hour.

Average Wind Speed at Diego Garcia

Average Wind Speed at Diego GarciawindyJanFebMarAprMayJunJulAugSepOctNovDec0 mph0 mph2 mph2 mph4 mph4 mph6 mph6 mph8 mph8 mph10 mph10 mph12 mph12 mph14 mph14 mph16 mph16 mph18 mph18 mph20 mph20 mphAug 817.7 mphAug 817.7 mphApr 48.5 mphApr 48.5 mphMay 2213.1 mphMay 2213.1 mphOct 2213.1 mphOct 2213.1 mphNowNow
The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.
JanFebMarAprMayJunJulAugSepOctNovDec
Wind Speed (mph) 10.911.09.09.212.415.717.217.516.213.510.99.6

The predominant average hourly wind direction at Diego Garcia varies throughout the year.

The wind is most often from the east for 8.1 months, from April 6 to December 10, with a peak percentage of 74% on June 22. The wind is most often from the west for 3.9 months, from December 10 to April 6, with a peak percentage of 51% on January 1.

Wind Direction at Diego Garcia

Wind Direction at Diego GarciaWEWJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%NowNowwesteastnorthsouth
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).

Diego Garcia 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 29 to May 9, with an average temperature above 84°F. The month of the year at Diego Garcia with the warmest water is April, with an average temperature of 84°F.

The time of year with cooler water lasts for 2.6 months, from July 2 to September 19, with an average temperature below 81°F. The month of the year at Diego Garcia with the coolest water is August, with an average temperature of 80°F.

Average Water Temperature at Diego Garcia

The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.
WaterJanFebMarAprMayJunJulAugSepOctNovDec
Temperature 83°F83°F84°F84°F83°F82°F81°F80°F81°F82°F83°F83°F

To characterize how pleasant the weather is at Diego Garcia 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 Diego Garcia for general outdoor tourist activities is from early July to early September, with a peak score in the first week of August.

Tourism Score at Diego Garcia

Tourism Score at Diego Garciabest timeJanFebMarAprMayJunJulAugSepOctNovDec002244668810105.25.22.42.4NowNowtemperaturetemperature cloudscloudsprecipitationprecipitationtourism 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 Diego Garcia for hot-weather activities is from late May to early September, with a peak score in the last week of July.

Beach/Pool Score at Diego Garcia

Beach/Pool Score at Diego Garciabest timeJanFebMarAprMayJunJulAugSepOctNovDec002244668810106.56.53.93.9NowNowtemperaturetemperature cloudscloudsprecipitationprecipitationbeach/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.

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 at Diego Garcia 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 at Diego Garcia

Time Spent in Various Temperature Bands and the Growing Season at Diego GarciaJanFebMarAprMayJunJulAugSepOctNovDec0%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 2100%Jul 2NowNowwarmhot
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 at Diego Garcia

Growing Degree Days at Diego GarciaJanFebMarAprMayJunJulAugSepOctNovDec0°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 301,800°FAug 301,800°FJun 3011,398°FJun 3011,398°FNowNow
The average growing degree days accumulated over the course of the year, with 25th to 75th and 10th to 90th percentile bands.

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 per square meter does not vary significantly over the course of the year, remaining within 0.5 kilowatt-hours of 5.0 kilowatt-hours throughout.

Average Daily Incident Shortwave Solar Energy at Diego Garcia

Average Daily Incident Shortwave Solar Energy at Diego GarciaJanFebMarAprMayJunJulAugSepOctNovDec0 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWh8 kWh8 kWhOct 315.5 kWhOct 315.5 kWhJun 294.6 kWhJun 294.6 kWhAug 185.3 kWhAug 185.3 kWhDec 115.3 kWhDec 115.3 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.
JanFebMarAprMayJunJulAugSepOctNovDec
Solar Energy (kWh) 4.84.95.15.05.04.74.85.35.45.45.55.2

For the purposes of this report, the geographical coordinates of Diego Garcia are -7.313 deg latitude, 72.411 deg longitude, and 0 ft elevation.

The topography within 2 miles of Diego Garcia is essentially flat, with a maximum elevation change of 95 feet and an average elevation above sea level of 3 feet. Within 10 miles is essentially flat (105 feet). Within 50 miles also contains only modest variations in elevation (105 feet).

The area within 2 miles of Diego Garcia is covered by water (100%), within 10 miles by water (100%), and within 50 miles by water (100%).

This report illustrates the typical weather at Diego Garcia, 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

Diego Garcia has a weather station that reported reliably enough during the analysis period that we have included it in our network. When available, historical temperature and dew point measurements are taken directly from this weather station. These records are obtained from NOAA's Integrated Surface Hourly data set, falling back on ICAO METAR records as required.

There are no other weather stations in our network within 200 kilometers of this location. Consequently, in the case of missing or erroneous measurements from this station, we fall back on NASA's MERRA-2 modern-era reanalysis , adjusted according to typical seasonal and diurnal differences between this station and the wide-area MERRA-2 reconstructed values.

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 © OpenStreetMap contributors.

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.

Please review our full terms contained on our Terms of Service page.