This report describes the typical weather at the Tromsø Airport (Tromsø, Norway) weather station over the course of an average July. 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 July is characterized by gradually rising daily high temperatures, with daily highs around 58°F throughout the month, exceeding 69°F or dropping below 48°F only one day in ten.
Over the course of July, 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 2:55 hours, implying an average day-over-day decrease of 5.6 minutes.
The shortest day of the month is July 31 with 21:06 hours of daylight; the longest day is July 2 with 24:00 hours of daylight.
Due to its extreme latitude, Tromsø experiences polar day during summer. During this period of time, the Sun remains continuously above the horizon for a prolonged period of time.
July begins in polar day, which lasts until July 25.
The earliest sunrise is at 1:14am on July 26; the latest sunset is at 12:29am on July 25; the latest sunrise is at 2:15am on July 31; the earliest sunset is at 11:21pm on July 31.
Daylight savings time is observed in 2012 but it neither starts nor ends in July, so the entire month is in daylight time.
The median cloud cover is 87% (mostly cloudy) and does not vary substantially over the course of the month.
On July 16, a representative day, the sky is clear or mostly clear 19% of the time, partly cloudy 19% of the time, and mostly cloudy or overcast 53% of the time.
The average probability that some form of precipitation will be observed in a given day is 64%, with little variation over the course of the month.
Throughout July, the most common forms of precipitation are moderate rain and light rain.
Moderate rain is the most severe precipitation observed during 70% of those days with precipitation. It is most likely around July 8, when it is observed during 45% of all days.
Light rain is the most severe precipitation observed during 21% of those days with precipitation. It is most likely around July 24, when it is observed during 14% of all days.
The likelihood of snow falling is highest around July 1, occurring in 2% of days.
Either snow rarely accumulates at this location in July or snow depth measurements are unavailable or unreliable.
The relative humidity typically ranges from 60% (mildly humid) to 94% (very humid) over the course of a typical July, rarely dropping below 42% (comfortable) and reaching as high as 100% (very humid).
The air is driest around July 1, at which time the relative humidity drops below 70% (humid) three days out of four; it is most humid around July 31, rising above 90% (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 July, the dew point typically varies from 40°F (dry) to 50°F (very comfortable) and is rarely below 34°F (dry) or above 56°F (comfortable).
Over the course of July typical wind speeds vary from 0 mph to 15 mph (calm to moderate breeze), rarely exceeding 22 mph (fresh breeze).
The highest average wind speed of 8 mph (gentle breeze) occurs around July 1, at which time the average daily maximum wind speed is 15 mph (moderate breeze).
The lowest average wind speed of 7 mph (light breeze) occurs around July 28, at which time the average daily maximum wind speed is 14 mph (moderate breeze).