Average Weather in September in Port-aux-Français French Southern Territories
Daily high temperatures are around 38°F, rarely falling below 34°F or exceeding 42°F.
Daily low temperatures are around 33°F, rarely falling below 29°F or exceeding 36°F.
For reference, on February 6, the hottest day of the year, temperatures in Port-aux-Français typically range from 40°F to 47°F, while on August 10, the coldest day of the year, they range from 32°F to 37°F.
Average High and Low Temperature in September
The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on September. 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 September
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
Akutan, Alaska, United States (10,094 miles away); Ólafsvík, Iceland (9,331 miles); and Vestmanna, Faroe Islands (8,797 miles) are the far-away foreign places with temperatures most similar to Port-aux-Français (view comparison).
The month of September in Port-aux-Français experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 53% throughout the month.
The clearest day of the month is September 29, with clear, mostly clear, or partly cloudy conditions 49% of the time.
For reference, on April 21, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 60%, while on November 21, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 50%.
Cloud Cover Categories in September
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 Port-aux-Français, the chance of a wet day over the course of September is essentially constant, remaining around 28% throughout.
For reference, the year's highest daily chance of a wet day is 37% on May 22, and its lowest chance is 26% on October 9.
Over the course of September in Port-aux-Français, the chance of a day with only rain remains an essentially constant 25% throughout, the chance of a day with mixed snow and rain remains an essentially constant 3% throughout, and the chance of a day with only snow remains an essentially constant 0% throughout.
Probability of Precipitation in September
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 September in Port-aux-Français is essentially constant, remaining about 1.5 inches throughout, and rarely exceeding 2.5 inches or falling below 0.7 inches.
Average Monthly Rainfall in September
We report snowfall in liquid-equivalent terms. The actual depth of new snowfall is typically between 5 and 10 times the liquid-equivalent amount, assuming the ground is frozen. As with rainfall, we consider the liquid-equivalent snowfall accumulated over a sliding 31-day period centered around each day.
The average sliding 31-day liquid-equivalent snowfall during September in Port-aux-Français is essentially constant, remaining about 0.1 inches throughout, and rarely exceeding 0.3 inches or falling below -0.0 inches.
Average Monthly Liquid-Equivalent Snowfall in September
Over the course of September in Port-aux-Français, the length of the day is rapidly increasing. From the start to the end of the month, the length of the day increases by 1 hour, 44 minutes, implying an average daily increase of 3 minutes, 35 seconds, and weekly increase of 25 minutes, 5 seconds.
The shortest day of the month is September 1, with 10 hours, 53 minutes of daylight and the longest day is September 30, with 12 hours, 37 minutes of daylight.
Hours of Daylight and Twilight in September
The latest sunrise of the month in Port-aux-Français is 6:52 AM on September 1 and the earliest sunrise is 1 hour, 2 minutes earlier at 5:50 AM on September 30.
The earliest sunset is 5:46 PM on September 1 and the latest sunset is 42 minutes later at 6:28 PM on September 30.
Daylight saving time is not observed in Port-aux-Français during 2021.
For reference, on December 21, the longest day of the year, the Sun rises at 4:09 AM and sets 16 hours, 16 minutes later, at 8:25 PM, while on June 21, the shortest day of the year, it rises at 8:15 AM and sets 8 hours, 10 minutes later, at 4:26 PM.
Sunrise & Sunset with Twilight in September
The figure below presents a compact representation of key lunar data for September 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. 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.
Moon Rise, Set & Phases in September
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 Port-aux-Français is essentially constant during September, remaining around 0% throughout.
Humidity Comfort Levels in September
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 Port-aux-Français is essentially constant during September, remaining within 0.2 miles per hour of 25.5 miles per hour throughout.
For reference, on September 3, the windiest day of the year, the daily average wind speed is 25.7 miles per hour, while on February 16, the calmest day of the year, the daily average wind speed is 22.1 miles per hour.
The highest daily average wind speed during September is 25.7 miles per hour on September 3.
Average Wind Speed in September
The hourly average wind direction in Port-aux-Français throughout September is predominantly from the west, with a peak proportion of 74% on September 4.
Wind Direction in September
Port-aux-Français 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 Port-aux-Français is essentially constant during September, remaining around 36°F throughout.
The lowest average surface water temperature during September is 36°F on September 7.
Average Water Temperature in September
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).
The growing season in Port-aux-Français typically lasts for 6.9 months (210 days), from around October 30 to around May 28, rarely starting before October 7 or after November 20, and rarely ending before May 4 or after June 21.
The month of September in Port-aux-Français is very likely fully outside of the growing season, with the chance that a given day is in the growing season gradually increasing from 0% to 3% over the course of the month.
Time Spent in Various Temperature Bands and the Growing Season in September
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 Port-aux-Français are essentially constant during September, remaining around 0°F throughout.
Growing Degree Days in September
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 Port-aux-Français is increasing during September, rising by 1.3 kWh, from 2.0 kWh to 3.3 kWh, over the course of the month.
Average Daily Incident Shortwave Solar Energy in September
For the purposes of this report, the geographical coordinates of Port-aux-Français are -49.350 deg latitude, 70.217 deg longitude, and 23 ft elevation.
The topography within 2 miles of Port-aux-Français contains only modest variations in elevation, with a maximum elevation change of 220 feet and an average elevation above sea level of 62 feet. Within 10 miles contains only modest variations in elevation (2,815 feet). Within 50 miles contains large variations in elevation (6,050 feet).
The area within 2 miles of Port-aux-Français is covered by water (41%), shrubs (24%), trees (16%), and grassland (12%), within 10 miles by water (45%) and bare soil (26%), and within 50 miles by water (79%) and bare soil (11%).
This report illustrates the typical weather in Port-aux-Français, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.
Port-aux-Français is further than 200 kilometers from the nearest reliable weather station, so the weather-related data on this page were taken entirely from NASA's MERRA-2 satellite-era reanalysis . 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.
The temperature and dew point estimates are corrected for the difference between the reference elevation of the MERRA-2 grid cell and the elevation of Port-aux-Français, according to the International Standard Atmosphere .
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.
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.
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.