Average Weather in January in Ofu American Samoa
Daily high temperatures are around 87°F, rarely falling below 84°F or exceeding 90°F.
Daily low temperatures are around 78°F, rarely falling below 75°F or exceeding 82°F. The lowest daily average low temperature is 78°F on January 18.
For reference, on February 26, the hottest day of the year, temperatures in Ofu typically range from 78°F to 88°F, while on August 9, the coldest day of the year, they range from 77°F to 84°F.
Average High and Low Temperature in January
The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on January. 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.
Average Hourly Temperature in January
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 month of January in Ofu experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 88% throughout the month. The highest chance of overcast or mostly cloudy conditions is 88% on January 7.
The clearest day of the month is January 31, with clear, mostly clear, or partly cloudy conditions 13% of the time.
For reference, on January 6, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 88%, while on August 23, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 59%.
Cloud Cover Categories in January
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Ofu, the chance of a wet day over the course of January is essentially constant, remaining around 59% throughout.
For reference, the year's highest daily chance of a wet day is 61% on January 9, and its lowest chance is 16% on July 30.
Probability of Precipitation in January
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 January in Ofu is increasing, starting the month at 9.1 inches, when it rarely exceeds 14.5 inches or falls below 4.0 inches, and ending the month at 9.8 inches, when it rarely exceeds 18.0 inches or falls below 3.8 inches.
The highest average 31-day accumulation is 10.0 inches on January 23.
Average Monthly Rainfall in January
Over the course of January in Ofu, the length of the day is essentially constant. The shortest day of the month is January 31, with 12 hours, 43 minutes of daylight and the longest day is January 1, with 12 hours, 57 minutes of daylight.
Hours of Daylight and Twilight in January
The earliest sunrise of the month in Ofu is 5:54 AM on January 1 and the latest sunrise is 17 minutes later at 6:10 AM on January 31.
The earliest sunset is 6:50 PM on January 1 and the latest sunset is 4 minutes later at 6:54 PM on January 21.
Daylight saving time is not observed in Ofu during 2018.
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 6:46 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 5:59 PM.
Sunrise & Sunset with Twilight in January
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 Ofu is essentially constant during January, 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 24, the least muggy day of the year, there are muggy conditions 98% of the time.
Humidity Comfort Levels in January
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
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 Ofu is essentially constant during January, remaining within 0.1 miles per hour of 11.1 miles per hour throughout.
For reference, on July 29, the windiest day of the year, the daily average wind speed is 15.2 miles per hour, while on April 8, the calmest day of the year, the daily average wind speed is 10.6 miles per hour.
Average Wind Speed in January
Wind Direction in January
Ofu 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 Ofu is essentially constant during January, remaining around 84°F throughout.
Average Water Temperature in January
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 Ofu 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 in January
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
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 Ofu are very rapidly increasing during January, increasing by 965°F, from 5,756°F to 6,721°F, over the course of the month.
Growing Degree Days in January
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 Ofu is essentially constant during January, remaining within 0.1 kWh of 5.2 kWh throughout.
Average Daily Incident Shortwave Solar Energy in January
For the purposes of this report, the geographical coordinates of Ofu are -14.175 deg latitude, -169.678 deg longitude, and 0 ft elevation.
The topography within 2 miles of Ofu contains very significant variations in elevation, with a maximum elevation change of 1,585 feet and an average elevation above sea level of 138 feet. Within 10 miles also contains very significant variations in elevation (1,850 feet). Within 50 miles contains very significant variations in elevation (3,156 feet).
The area within 2 miles of Ofu is covered by water (100%), within 10 miles by water (100%), and within 50 miles by water (100%).
This report illustrates the typical weather in Ofu year round, 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, Pago Pago International Airport, in our network suitable to be used as a proxy for the historical temperature and dew point records of Ofu.
At a distance of 113 kilometers from Ofu, 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 Ofu 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.
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.
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.