This report describes the typical weather at the Tromsø Airport (Tromsø, Norway) weather station over the course of an average December. 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%).
The month of December is characterized by gradually falling daily high temperatures, with daily highs ranging from 34°F to 30°F over the course of the month, exceeding 41°F or dropping below 19°F only one day in ten.
Over the course of December, the length of the day is essentially constant.
Due to its extreme latitude, Tromsø experiences polar night during winter. During this period of time, the Sun remains continuously below the horizon for a prolonged period of time.
This station is in polar night during all of December, meaning the Sun is continuously below the horizon.
Daylight savings time is observed in 2012 but it neither starts nor ends in December, so the entire month is in standard time.
The median cloud cover is 81% (mostly cloudy) and does not vary substantially over the course of the month.
On December 16, a representative day, the sky is clear or mostly clear 20% of the time, partly cloudy 20% of the time, and mostly cloudy or overcast 44% of the time.
The average probability that some form of precipitation will be observed in a given day is 73%, with little variation over the course of the month.
Throughout December, the most common forms of precipitation are moderate snow, light snow, and moderate rain.
Moderate snow is the most severe precipitation observed during 63% of those days with precipitation. It is most likely around December 31, when it is observed during 48% of all days.
Light snow is the most severe precipitation observed during 18% of those days with precipitation. It is most likely around December 26, when it is observed during 14% of all days.
Moderate rain is the most severe precipitation observed during 11% of those days with precipitation. It is most likely around December 1, when it is observed during 11% of all days.
The likelihood of snow falling is highest around December 30, occurring in 64% of days.
Accumulation at this location in December is extremely unlikely. The chances of there being snow on the ground are highest around December 31, occurring 4% of the time.
The snow is typically at its deepest on December 14, with a median depth of 9.6"; the depth exceeds 10.6" only one year out of ten.
The relative humidity typically ranges from 64% (mildly humid) to 92% (very humid) over the course of a typical December, rarely dropping below 49% (comfortable) and reaching as high as 100% (very humid).
The air is driest around December 25, at which time the relative humidity drops below 73% (humid) three days out of four; it is most humid around December 11, rising above 89% (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 typical December, the dew point typically varies from 15°F (dry) to 28°F (dry) and is rarely below 4°F (dry) or above 36°F (dry).
Over the course of December typical wind speeds vary from 1 mph to 19 mph (light air to fresh breeze), rarely exceeding 31 mph (high wind).
The highest average wind speed of 11 mph (gentle breeze) occurs around December 24, at which time the average daily maximum wind speed is 19 mph (fresh breeze).
The lowest average wind speed of 10 mph (gentle breeze) occurs around December 1, at which time the average daily maximum wind speed is 19 mph (fresh breeze).