This report describes the typical weather at the Tromsø Airport (Tromsø, Norway) weather station over the course of an average year. It is based on the historical records from 1974 to 2012. Earlier records are either unavailable or unreliable.
Tromsø has a humid subarctic continental climate with cool summers and no dry season. The area within 25 mi of this station is covered by tundra (47%), oceans and seas (36%), and forests (14%).
Over the course of a year, the temperature typically varies from 20Â°F to 60Â°F and is rarely below 9Â°F or above 69Â°F.
The warm season lasts from June 14 to September 3 with an average daily high temperature above 53Â°F. The hottest day of the year is July 25, with an average high of 60Â°F and low of 49Â°F.
The cold season lasts from November 16 to March 31 with an average daily high temperature below 35Â°F. The coldest day of the year is February 1, with an average low of 20Â°F and high of 28Â°F.
The length of the day varies significantly over the course of the year. The shortest day is December 21 with 0:00 hours of daylight; the longest day is June 20 with 24:00 hours of daylight.
Due to its extreme latitude, Tromsø experiences polar day (also known as the midnight Sun) during summer and polar night during winter. 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 summer, the Sun is continuously above the horizon for 67 days, from May 18 to July 24.
In winter, the Sun is continuously below the horizon for 49 days, from November 27 to January 15.
Daylight savings time (DST) is observed in this location during 2012, starting in the spring on March 25 and ending in the fall on October 28.
The median cloud cover is 85% (mostly cloudy) and does not vary substantially over the course of the year.
On January 6, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 40% of the time, and overcast or mostly cloudy 43% of the time.
On September 26, the cloudiest day of the year, the sky is overcast, mostly cloudy, or partly cloudy 77% of the time, and clear or mostly clear 16% of the time.
The probability that precipitation will be observed at this location varies throughout the year. Precipitation is most likely around September 30, occurring in 77% of days. Precipitation is least likely around July 24, occurring in 64% of days.
Over the entire year, the most common forms of precipitation are moderate rain, moderate snow, light snow, and light rain.
Moderate rain is the most severe precipitation observed during 36% of those days with precipitation. It is most likely around September 15, when it is observed during 49% of all days.
Moderate snow is the most severe precipitation observed during 36% of those days with precipitation. It is most likely around January 17, when it is observed during 50% of all days.
Light snow is the most severe precipitation observed during 13% of those days with precipitation. It is most likely around February 7, when it is observed during 15% of all days.
Light rain is the most severe precipitation observed during 12% of those days with precipitation. It is most likely around August 9, when it is observed during 15% of all days.
During the warm season, which lasts from June 14 to September 3, there is a 66% average chance that precipitation will be observed at some point during a given day. When precipitation does occur it is most often in the form of moderate rain (69% of days with precipitation have at worst moderate rain), light rain (21%), and drizzle (6%).
During the cold season, which lasts from November 16 to March 31, there is a 72% average chance that precipitation will be observed at some point during a given day. When precipitation does occur it is most often in the form of moderate snow (64% of days with precipitation have at worst moderate snow), light snow (19%), and moderate rain (10%).
The likelihood of snow falling is highest around February 6, occurring in 66% of days. The season in which it is relatively likely for snow to fall spans from October 7 to May 18.
During peak snow season, accumulation at this location on a given day is very unlikely. The chances of there being snow on the ground are highest around February 6, occurring 7% of the time.
The snow is typically at its deepest on February 16, with a median depth of 19.8"; the depth exceeds 28.7" only one year out of ten.
The relative humidity typically ranges from 55% (mildly humid) to 94% (very humid) over the course of the year, rarely dropping below 38% (comfortable) and reaching as high as 100% (very humid).
The air is driest around May 17, at which time the relative humidity drops below 64% (mildly humid) three days out of four; it is most humid around September 9, exceeding 92% (very humid) three days out of four.
Dew point is often a better measure of how comfortable a person will find the weather than relative humidity because it more directly relates to whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid.
Over the course of a year, the dew point typically varies from 13Â°F (dry) to 50Â°F (very comfortable) and is rarely below 2Â°F (dry) or above 56Â°F (comfortable).
Over the course of the year typical wind speeds vary from 0 mph to 21 mph (calm to fresh breeze), rarely exceeding 31 mph (high wind).
The highest average wind speed of 12 mph (moderate breeze) occurs around February 16, at which time the average daily maximum wind speed is 21 mph (fresh breeze).
The lowest average wind speed of 6 mph (light breeze) occurs around August 7, at which time the average daily maximum wind speed is 13 mph (moderate breeze).