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Average Weather at Antonio B. Won Pat International Airport Guam

At Antonio B. Won Pat International Airport, the wet season is overcast; the dry season is partly cloudy; and it is hot, oppressive, and windy year round. Over the course of the year, the temperature typically varies from 76°F to 88°F and is rarely below 74°F or above 90°F.

Based on the beach/pool score, the best time of year to visit Antonio B. Won Pat International Airport for hot-weather activities is from mid December to late April.

Climate Summary

hotJanFebMarAprMayJunJulAugSepOctNovDec47%47%7%7%overcastclearprecipitation: 9.3 inprecipitation: 9.3 in0.6 in0.6 inmuggy: 100%muggy: 100%96%96%beach/pool score: 7.1beach/pool score: 7.13.93.9
Click on each chart for more information.

Temperature

The temperature at Antonio B. Won Pat International Airport 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 at Antonio B. Won Pat International AirportJanFebMarAprMayJunJulAugSepOctNovDec0°F10°F20°F30°F40°F50°F60°F70°F80°F90°F100°FFeb 1285°FFeb 1285°FJun 588°FJun 588°F76°F76°F79°F79°FApr 2688°FApr 2688°FJul 988°FJul 988°FDec 2786°FDec 2786°F78°F78°F78°F78°F77°F77°FLowHigh
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 at Antonio B. Won Pat International AirportJanFebMarAprMayJunJulAugSepOctNovDec12 AM4 AM8 AM12 PM4 PM8 PM12 AMwarmhot
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.

Cartagena, Colombia (9,228 miles away) is the far-away foreign place with temperatures most similar to Antonio B. Won Pat International Airport (view comparison).

Clouds

At Antonio B. Won Pat International Airport, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.

The clearer part of the year at Antonio B. Won Pat International Airport begins around November 15 and lasts for 5.6 months, ending around May 4. On February 18, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 47% of the time, and overcast or mostly cloudy 53% of the time.

The cloudier part of the year begins around May 4 and lasts for 6.4 months, ending around November 15. On August 7, the cloudiest day of the year, the sky is overcast or mostly cloudy 93% of the time, and clear, mostly clear, or partly cloudy 7% of the time.

Cloud Cover Categories

Cloud Cover Categories at Antonio B. Won Pat International AirportclearerclearercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Feb 1847%Feb 1847%Aug 77%Aug 77%Nov 1527%Nov 1527%May 428%May 428%clearmostly 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 at Antonio B. Won Pat International Airport varies very significantly throughout the year.

The wetter season lasts 4.5 months, from July 3 to November 18, with a greater than 37% chance of a given day being a wet day. The chance of a wet day peaks at 67% on August 12.

The drier season lasts 7.5 months, from November 18 to July 3. The smallest chance of a wet day is 7% on March 27.

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 67% on August 12.

Daily Chance of Precipitation

Daily Chance of Precipitation at Antonio B. Won Pat International AirportwetdrydryJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Aug 1267%Aug 1267%Mar 277%Mar 277%Jan 123%Jan 123%Jul 337%Jul 337%Nov 1837%Nov 1837%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. Antonio B. Won Pat International Airport experiences extreme seasonal variation in monthly rainfall.

Rain falls throughout the year at Antonio B. Won Pat International Airport. The most rain falls during the 31 days centered around August 22, with an average total accumulation of 9.3 inches.

The least rain falls around March 26, with an average total accumulation of 0.6 inches.

Average Monthly Rainfall

Average Monthly Rainfall at Antonio B. Won Pat International AirportJanFebMarAprMayJunJulAugSepOctNovDec0 in5 in10 in15 inAug 229.3 inAug 229.3 inMar 260.6 inMar 260.6 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 at Antonio B. Won Pat International Airport varies over the course of the year. In 2018, the shortest day is December 22, with 11 hours, 20 minutes of daylight; the longest day is June 21, with 12 hours, 55 minutes of daylight.

Hours of Daylight and Twilight

Hours of Daylight and Twilight at Antonio B. Won Pat International AirportJanFebMarAprMayJunJulAugSepOctNovDec0 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hr12 hr, 6 minMar 2112 hr, 6 minMar 2112 hr, 55 minJun 2112 hr, 55 minJun 2112 hr, 7 minSep 2312 hr, 7 minSep 2311 hr, 20 minDec 2211 hr, 20 minDec 22nightnightday
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 5:52 AM on June 2, and the latest sunrise is 56 minutes later at 6:48 AM on January 24. The earliest sunset is at 5:50 PM on November 21, and the latest sunset is 1 hour, 2 minutes later at 6:52 PM on July 10.

Daylight saving time (DST) is not observed at Antonio B. Won Pat International Airport during 2018.

Sunrise & Sunset with Twilight

Sunrise & Sunset with Twilight at Antonio B. Won Pat International AirportJanFebMarAprMayJunJulAugSepOctNovDec2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJun 25:52 AMJun 25:52 AM6:52 PMJul 106:52 PMJul 10Nov 215:50 PMNov 215:50 PM6:48 AMJan 246:48 AMJan 24daynightnightSolarMidnightSolarMidnightSolarNoonSunriseSunset
The solar day over the course of the year 2018. 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.

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 at Antonio B. Won Pat International Airport, 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

Humidity Comfort Levels at Antonio B. Won Pat International AirportJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Feb 1196%Feb 1196%100%Oct 18100%Oct 18miserablemiserableoppressiveoppressivemuggymuggy
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 at Antonio B. Won Pat International Airport experiences significant seasonal variation over the course of the year.

The windier part of the year lasts for 6.3 months, from October 31 to May 8, with average wind speeds of more than 13.8 miles per hour. The windiest day of the year is December 26, with an average hourly wind speed of 17.2 miles per hour.

The calmer time of year lasts for 5.7 months, from May 8 to October 31. The calmest day of the year is July 26, with an average hourly wind speed of 10.4 miles per hour.

Average Wind Speed

Average Wind Speed at Antonio B. Won Pat International AirportwindywindyJanFebMarAprMayJunJulAugSepOctNovDec0 mph2 mph4 mph6 mph8 mph10 mph12 mph14 mph16 mph18 mph20 mph22 mphDec 2617.2 mphDec 2617.2 mphJul 2610.4 mphJul 2610.4 mphOct 3113.8 mphOct 3113.8 mphMay 813.8 mphMay 813.8 mph
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 at Antonio B. Won Pat International Airport is from the east throughout the year.

Wind Direction

Wind Direction at Antonio B. Won Pat International AirportJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%westeastsouthnorth
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

Antonio B. Won Pat International Airport 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 does not vary significantly over the course of the year, remaining within 2°F of 83°F throughout.

Average Water Temperature

Average Water Temperature at Antonio B. Won Pat International AirportJanFebMarAprMayJunJulAugSepOctNovDec79°F80°F81°F82°F83°F84°F85°F86°F87°FJul 3185°FJul 3185°F81°FFeb 2381°FFeb 23Jun 384°FJun 384°FNov 1284°FNov 1284°FJan 1682°FJan 1682°FApr 582°FApr 582°F
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 at Antonio B. Won Pat International Airport 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 Antonio B. Won Pat International Airport for general outdoor tourist activities is from early January to early April, with a peak score in the third week of February.

Tourism Score

Tourism Score at Antonio B. Won Pat International Airportbest timeJanFebMarAprMayJunJulAugSepOctNovDec02468106.66.62.72.7precipitationprecipitationcloudscloudstemperaturetemperaturetourism 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 Antonio B. Won Pat International Airport for hot-weather activities is from mid December to late April, with a peak score in the second week of March.

Beach/Pool Score

Beach/Pool Score at Antonio B. Won Pat International Airportbest timeJanFebMarAprMayJunJulAugSepOctNovDec02468107.17.13.93.9 precipitationprecipitationcloudscloudstemperaturetemperaturebeach/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 at Antonio B. Won Pat International Airport 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 at Antonio B. Won Pat International AirportJanFebMarAprMayJunJulAugSepOctNovDec0%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 3warmhotcomfortable
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 at Antonio B. Won Pat International AirportJanFebMarAprMayJunJulAugSepOctNovDec0°F2,000°F4,000°F6,000°F8,000°F10,000°FJan 490°FJan 490°FJan 31900°FJan 31900°FDec 3111,426°FDec 3111,426°F
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 significant seasonal variation over the course of the year.

The brighter period of the year lasts for 2.4 months, from February 28 to May 10, with an average daily incident shortwave energy per square meter above 6.4 kWh. The brightest day of the year is April 4, with an average of 7.0 kWh.

The darker period of the year lasts for 4.0 months, from July 5 to November 6, with an average daily incident shortwave energy per square meter below 4.5 kWh. The darkest day of the year is August 10, with an average of 3.9 kWh.

Average Daily Incident Shortwave Solar Energy

Average Daily Incident Shortwave Solar Energy at Antonio B. Won Pat International AirportbrightdarkJanFebMarAprMayJunJulAugSepOctNovDec0 kWh1 kWh2 kWh3 kWh4 kWh5 kWh6 kWh7 kWh8 kWhApr 47.0 kWhApr 47.0 kWhAug 103.9 kWhAug 103.9 kWhNov 64.5 kWhNov 64.5 kWh
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 Antonio B. Won Pat International Airport are 13.483 deg latitude, 144.798 deg longitude, and 184 ft elevation.

The topography within 2 miles of Antonio B. Won Pat International Airport contains significant variations in elevation, with a maximum elevation change of 623 feet and an average elevation above sea level of 204 feet. Within 10 miles contains significant variations in elevation (1,050 feet). Within 50 miles also contains very significant variations in elevation (1,332 feet).

The area within 2 miles of Antonio B. Won Pat International Airport is covered by grassland (58%) and cropland (25%), within 10 miles by water (68%) and cropland (16%), and within 50 miles by water (98%).

Data Sources

This report illustrates the typical weather at Antonio B. Won Pat International Airport, 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

Antonio B. Won Pat International Airport 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.

In the case of missing or erroneous measurements from this station, we fall back on records from nearby stations, adjusted according to typical seasonal and diurnal intra-station differences. For a given day of the year and hour of the day, the fallback station is selected to minimize the prediction error over the years for which there are measurements for both stations.

In this case, the only station close and reliable enough to use as a fallback is USAF Andersen Air Force Base.

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Tables of the Sun, Moon and Planets , 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 aiports 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.