This report describes the typical weather at the Tromsø Airport (Tromsø, Norway) weather station over the course of an average April. 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 April is characterized by rising daily high temperatures, with daily highs increasing from 35°F to 42°F over the course of the month, exceeding 48°F or dropping below 28°F only one day in ten.
Over the course of April, the length of the day is very rapidly increasing. From the start to the end of the month, the length of the day increases by 4:33 hours, implying an average day-over-day increase of 9.1 minutes.
The shortest day of the month is April 1 with 14:06 hours of daylight; the longest day is April 30 with 18:39 hours of daylight.
The earliest sunrise is at 3:24am on April 30; the latest sunset is at 10:04pm on April 30; the latest sunrise is at 5:46am on April 1; the earliest sunset is at 7:53pm on April 1.
Daylight savings time is observed in 2012 but it neither starts nor ends in April, so the entire month is in daylight time.
The median cloud cover is 84% (mostly cloudy) and does not vary substantially over the course of the month.
On April 15, 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 47% of the time.
The average probability that some form of precipitation will be observed in a given day is 69%, with little variation over the course of the month.
Throughout April, the most common forms of precipitation are moderate snow, moderate rain, and light snow.
Moderate snow is the most severe precipitation observed during 47% of those days with precipitation. It is most likely around April 1, when it is observed during 39% of all days.
Moderate rain is the most severe precipitation observed during 21% of those days with precipitation. It is most likely around April 30, when it is observed during 21% of all days.
Light snow is the most severe precipitation observed during 19% of those days with precipitation. It is most likely around April 2, when it is observed during 14% of all days.
The likelihood of snow falling is highest around April 1, occurring in 54% of days.
Accumulation at this location in April is very unlikely. The chances of there being snow on the ground are highest around April 1, occurring 5% of the time.
The snow is typically at its deepest on April 3, with a median depth of 9.9"; the depth exceeds 13.6" only one year out of ten.
The relative humidity typically ranges from 56% (mildly humid) to 90% (very humid) over the course of a typical April, rarely dropping below 40% (comfortable) and reaching as high as 100% (very humid).
The air is driest around April 29, at which time the relative humidity drops below 65% (mildly humid) three days out of four; it is most humid around April 12, rising above 85% (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 April, the dew point typically varies from 18°F (dry) to 33°F (dry) and is rarely below 9°F (dry) or above 39°F (dry).
Over the course of April typical wind speeds vary from 0 mph to 17 mph (calm to moderate breeze), rarely exceeding 27 mph (strong breeze).
The highest average wind speed of 9 mph (gentle breeze) occurs around April 2, at which time the average daily maximum wind speed is 17 mph (moderate breeze).
The lowest average wind speed of 8 mph (gentle breeze) occurs around April 28, at which time the average daily maximum wind speed is 15 mph (moderate breeze).