May Weather in American Samoa American Samoa

Daily high temperatures are around 86°F, rarely falling below 83°F or exceeding 89°F.

Daily low temperatures are around 78°F, rarely falling below 75°F or exceeding 82°F.

For reference, on February 26, the hottest day of the year, temperatures in American Samoa typically range from 79°F to 88°F, while on July 23, the coldest day of the year, they range from 77°F to 84°F.

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

© OpenStreetMap contributors

Compare American Samoa to:

CompareMap

The month of May in American Samoa experiences gradually decreasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy decreasing from 69% to 61%.

The clearest day of the month is May 31, with clear, mostly clear, or partly cloudy conditions 39% of the time.

For reference, on January 7, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 88%, while on August 25, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 61%.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In American Samoa, the chance of a wet day over the course of May is very rapidly decreasing, starting the month at 46% and ending it at 37%.

For reference, the year's highest daily chance of a wet day is 62% on January 16, and its lowest chance is 17% on July 29.

Rainfall

To show variation within the month and not just the monthly total, we show the rainfall accumulated over a sliding 31-day period centered around each day.

The average sliding 31-day rainfall during May in American Samoa is rapidly decreasing, starting the month at 5.4 inches, when it rarely exceeds 10.6 inches or falls below 1.6 inches, and ending the month at 3.4 inches, when it rarely exceeds 6.2 inches or falls below 0.8 inches.

Over the course of May in American Samoa, the length of the day is essentially constant. The shortest day of the month is May 31, with 11 hours, 20 minutes of daylight and the longest day is May 1, with 11 hours, 35 minutes of daylight.

The earliest sunrise of the month in American Samoa is 6:27 AM on May 1 and the latest sunrise is 8 minutes later at 6:35 AM on May 31.

The latest sunset is 6:02 PM on May 1 and the earliest sunset is 7 minutes earlier at 5:55 PM on May 30.

Daylight saving time is not observed in American Samoa during 2026.

For reference, on December 21, the longest day of the year, the Sun rises at 5:47 AM and sets 12 hours, 58 minutes later, at 6:45 PM, while on June 21, the shortest day of the year, it rises at 6:41 AM and sets 11 hours, 17 minutes later, at 5:58 PM.

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.

The figure below presents a compact representation of key lunar data for May 2026. 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. The label associated with each bar indicates the date and time that the phase is obtained, and the companion time labels indicate the rise and set times of the Moon for the nearest time interval in which the moon is above the horizon.

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 chance that a given day will be muggy in American Samoa is essentially constant during May, remaining around 100% throughout.

For reference, on January 1, the muggiest day of the year, there are muggy conditions 100% of the time, while on July 23, the least muggy day of the year, there are muggy conditions 98% of the time.

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 American Samoa is rapidly increasing during May, increasing from 11.3 miles per hour to 13.7 miles per hour over the course of the month.

For reference, on July 29, the windiest day of the year, the daily average wind speed is 15.0 miles per hour, while on March 9, the calmest day of the year, the daily average wind speed is 10.4 miles per hour.

The hourly average wind direction in American Samoa throughout May is predominantly from the east, with a peak proportion of 80% on May 31.

American Samoa 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 surface water temperature in American Samoa is essentially constant during May, remaining around 84°F throughout.

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 American Samoa 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.

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.

The average accumulated growing degree days in American Samoa are very rapidly increasing during May, increasing by 950°F, from 9,605°F to 10,555°F, over the course of the month.

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 in American Samoa is essentially constant during May, remaining within 0.1 kWh of 4.3 kWh throughout.

The lowest average daily incident shortwave solar energy during May is 4.2 kWh on May 30.

For the purposes of this report, the geographical coordinates of American Samoa are -14.234 deg latitude, -169.478 deg longitude, and 16 ft elevation.

The topography within 2 miles of American Samoa contains large variations in elevation, with a maximum elevation change of 3,110 feet and an average elevation above sea level of 1,215 feet. Within 10 miles also contains large variations in elevation (3,123 feet). Within 50 miles also contains large variations in elevation (3,156 feet).

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