Average Weather in Longyearbyen Svalbard & Jan Mayen
In Longyearbyen, the summers are short, chilly, and dry; the winters are long, frigid, snowy, and windy; and it is overcast year round. Over the course of the year, the temperature typically varies from 3°F to 47°F and is rarely below -19°F or above 53°F.
The warm season lasts for 2.6 months, from June 17 to September 4, with an average daily high temperature above 40°F. The hottest day of the year is July 22, with an average high of 47°F and low of 41°F.
The cold season lasts for 5.0 months, from November 22 to April 22, with an average daily high temperature below 21°F. The coldest day of the year is February 18, with an average low of 3°F and high of 14°F.
Average High and Low Temperature
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
In Longyearbyen, 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 in Longyearbyen begins around April 19 and lasts for 5.7 months, ending around October 11. On May 28, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 40% of the time, and overcast or mostly cloudy 60% of the time.
The cloudier part of the year begins around October 11 and lasts for 6.3 months, ending around April 19. On January 20, the cloudiest day of the year, the sky is overcast or mostly cloudy 92% of the time, and clear, mostly clear, or partly cloudy 8% of the time.
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Longyearbyen varies throughout the year.
The wetter season lasts 8.9 months, from July 22 to April 18, with a greater than 18% chance of a given day being a wet day. The chance of a wet day peaks at 27% on September 25.
The drier season lasts 3.1 months, from April 18 to July 22. The smallest chance of a wet day is 9% on May 29.
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 in Longyearbyen changes throughout the year.
Snow alone is the most common for 7.2 months, from October 13 to May 19. The highest chance of a day with snow alone is 18% on January 5.
Rain alone is the most common for 4.8 months, from May 19 to October 13. The highest chance of a day with rain alone is 24% on September 2.
Daily Chance of Precipitation
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. Longyearbyen experiences some seasonal variation in monthly rainfall.
The rainy period of the year lasts for 5.2 months, from June 13 to November 18, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around September 12, with an average total accumulation of 1.4 inches.
The rainless period of the year lasts for 6.8 months, from November 18 to June 13. The least rain falls around April 9, with and average total accumulation of 0.2 inches.
Average Monthly Rainfall
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. Colder, drier snow tends to be on the higher end of that range and warmer, wetter snow on the lower end.
As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. Longyearbyen experiences significant seasonal variation in monthly liquid-equivalent snowfall.
The snowy period of the year lasts for 9.0 months, from September 8 to June 8, with a sliding 31-day liquid-equivalent snowfall of at least 0.1 inches. The most snow falls during the 31 days centered around December 31, with an average total liquid-equivalent accumulation of 1.0 inches.
The snowless period of the year lasts for 3.0 months, from June 8 to September 8. The least snow falls around July 25, with an average total liquid-equivalent accumulation of 0.0 inches.
Average Liquid-Equivalent Monthly Snowfall
Due to its extreme latitude, Longyearbyen 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.
In the summer in Longyearbyen during 2017, the Sun is continuously above the horizon for 4.2 months, rising at 1:30 AM on April 18, and not setting again until 12:22 AM on August 25.
In the winter in Longyearbyen during 2017, the Sun is continuously below the horizon for 3.6 months, setting at 12:53 PM on October 26, and not rising again until 11:46 AM on February 15.
Hours of Daylight and Twilight
Daylight saving time (DST) is observed in Longyearbyen during 2017, starting in the spring on March 26, lasting 7.1 months, and ending in the fall on October 29.
Sunrise & Sunset with Twilight and Daylight Saving Time
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 in Longyearbyen, 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, remaining a virtually constant 0% throughout.
Humidity Comfort Levels
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 Longyearbyen experiences significant seasonal variation over the course of the year.
The windier part of the year lasts for 6.0 months, from October 19 to April 20, with average wind speeds of more than 5.6 miles per hour. The windiest day of the year is January 2, with an average hourly wind speed of 7.2 miles per hour.
The calmer time of year lasts for 6.0 months, from April 20 to October 19. The calmest day of the year is June 21, with an average hourly wind speed of 4.0 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in Longyearbyen is from the east throughout the year.
Longyearbyen 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 experiences some seasonal variation over the course of the year.
The time of year with warmer water lasts for 1.7 months, from July 12 to September 2, with an average temperature above 38°F. The day of the year with the warmest water is August 6, with an average temperature of 39°F.
The time of year with cooler water lasts for 7.5 months, from October 23 to June 9, with an average temperature below 34°F. The day of the year with the coolest water is February 14, with an average temperature of 32°F.
Average Water Temperature
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 extreme seasonal variation over the course of the year.
The brighter period of the year lasts for 2.1 months, from May 13 to July 15, with an average daily incident shortwave energy per square meter above 4.7 kWh. The brightest day of the year is June 8, with an average of 5.9 kWh.
The darker period of the year lasts for 6.5 months, from September 12 to March 29, with an average daily incident shortwave energy per square meter below 1.2 kWh. The darkest day of the year is January 1, with an average of 0.0 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Longyearbyen are 78.223 deg latitude, 15.647 deg longitude, and 240 ft elevation.
The topography within 2 miles of Longyearbyen contains very significant variations in elevation, with a maximum elevation change of 1,594 feet and an average elevation above sea level of 358 feet. Within 10 miles contains very significant variations in elevation (3,448 feet). Within 50 miles also contains extreme variations in elevation (4,160 feet).
The area within 2 miles of Longyearbyen is covered by snow and glaciers (36%), water (35%), and sparse vegetation (25%), within 10 miles by snow and glaciers (50%) and water (30%), and within 50 miles by snow and glaciers (60%) and water (28%).
This report illustrates the typical weather in Longyearbyen, 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, Svalbard Airport, Longyear, in our network suitable to be used as a proxy for the historical temperature and dew point records of Longyearbyen.
At a distance of 5 kilometers from Longyearbyen, 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 Longyearbyen 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.