Average Weather in September in Upernavik Greenland
Daily high temperatures decrease by 9°F, from 42°F to 32°F, rarely falling below 27°F or exceeding 47°F.
Daily low temperatures decrease by 9°F, from 37°F to 28°F, rarely falling below 22°F or exceeding 41°F.
For reference, on July 24, the hottest day of the year, temperatures in Upernavik typically range from 42°F to 47°F, while on February 28, the coldest day of the year, they range from -10°F to -2°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
The month of September in Upernavik experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 57% throughout the month. The lowest chance of overcast or mostly cloudy conditions is 54% on September 7.
The clearest day of the month is September 7, with clear, mostly clear, or partly cloudy conditions 46% of the time.
For reference, on January 1, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 81%, while on June 2, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 49%.
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 Upernavik, the chance of a wet day over the course of September is decreasing, starting the month at 19% and ending it at 15%.
For reference, the year's highest daily chance of a wet day is 24% on August 7, and its lowest chance is 4% on February 13.
Over the course of September in Upernavik, the chance of a day with only rain decreases from 19% to 7%, the chance of a day with mixed snow and rain remains an essentially constant 1% throughout, and the chance of a day with only snow increases from 0% to 7%.
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 Upernavik is decreasing, starting the month at 1.6 inches, when it rarely exceeds 3.3 inches or falls below 0.2 inches, and ending the month at 0.6 inches, when it rarely exceeds 1.5 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 Upernavik is gradually increasing, starting the month at 0.1 inches, when it rarely exceeds 0.2 inches or falls below -0.0 inches, and ending the month at 0.4 inches, when it rarely exceeds 1.0 inches.
Average Monthly Liquid-Equivalent Snowfall in September
Due to its extreme latitude, Upernavik experiences polar day (also known as the midnight Sun) during the summer and polar night during the winter. These are periods of time in which the sun is continuously above or below the horizon for more than one day. The precise start and end dates of polar day and night vary from year to year and depend on the precise location and elevation of the observer, and the local topography.
Neither polar day nor polar night occur during the month of September.
Over the course of September in Upernavik, the length of the day is very rapidly decreasing. From the start to the end of the month, the length of the day decreases by 4 hours, 59 minutes, implying an average daily decrease of 10 minutes, 19 seconds, and weekly decrease of 1 hour, 12 minutes, 14 seconds.
The shortest day of the month is September 30, with 11 hours, 3 minutes of daylight and the longest day is September 1, with 16 hours, 3 minutes of daylight.
Hours of Daylight and Twilight in September
The earliest sunrise of the month in Upernavik is 5:41 AM on September 1 and the latest sunrise is 2 hours, 20 minutes later at 8:01 AM on September 30.
The latest sunset is 9:43 PM on September 1 and the earliest sunset is 2 hours, 39 minutes earlier at 7:05 PM on September 30.
Daylight saving time is observed in Upernavik during 2021, but it neither starts nor ends during September, so the entire month is in daylight saving time.
Sunrise & Sunset with Twilight and Daylight Saving Time 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 Upernavik 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 Upernavik is increasing during September, increasing from 8.4 miles per hour to 9.5 miles per hour over the course of the month.
For reference, on November 10, the windiest day of the year, the daily average wind speed is 11.4 miles per hour, while on July 13, the calmest day of the year, the daily average wind speed is 6.7 miles per hour.
Average Wind Speed in September
The hourly average wind direction in Upernavik throughout September is predominantly from the south, with a peak proportion of 38% on September 2.
Wind Direction in September
Upernavik 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 Upernavik is gradually decreasing during September, falling by 3°F, from 39°F to 36°F, over the course of the month.
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 Upernavik typically lasts for 2.7 months (81 days), from around June 19 to around September 9, rarely starting before May 30 or after July 18, and rarely ending before August 14 or after September 28.
During September in Upernavik, the chance that a given day is within the growing season is very rapidly decreasing falling from 68% to 7% 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 Upernavik are essentially constant during September, remaining around 13°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 Upernavik is rapidly decreasing during September, falling by 1.6 kWh, from 2.6 kWh to 1.0 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 Upernavik are 72.787 deg latitude, -56.155 deg longitude, and 3 ft elevation.
The topography within 2 miles of Upernavik contains significant variations in elevation, with a maximum elevation change of 659 feet and an average elevation above sea level of 49 feet. Within 10 miles contains significant variations in elevation (3,356 feet). Within 50 miles also contains extreme variations in elevation (3,816 feet).
The area within 2 miles of Upernavik is covered by water (87%), within 10 miles by water (73%) and sparse vegetation (13%), and within 50 miles by water (64%) and snow and glaciers (18%).
This report illustrates the typical weather in Upernavik, 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, Upernavik Airport, in our network suitable to be used as a proxy for the historical temperature and dew point records of Upernavik.
At a distance of 2 kilometer from Upernavik, 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 Upernavik 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 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 © 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.