Average Weather In May For Tromsø, Norway

Location

This report describes the typical weather at the Tromsø Airport (Tromsø, Norway) weather station over the course of an average May. 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%).

Temperature

The month of May is characterized by rising daily high temperatures, with daily highs increasing from 42°F to 50°F over the course of the month, exceeding 59°F or dropping below 36°F only one day in ten.

Daily High and Low Temperature in May

The daily average low (blue) and high (red) temperature with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).
Daily low temperatures range from 33°F to 40°F, falling below 26°F or exceeding 45°F only one day in ten.

Fraction of Time Spent in Various Temperature Bands in May

The average fraction of time spent in various temperature bands: frigid (below 15°F), freezing (15°F to 32°F), cold (32°F to 50°F), cool (50°F to 65°F), comfortable (65°F to 75°F), warm (75°F to 85°F), hot (85°F to 100°F) and sweltering (above 100°F).

Sun

Over the course of May, 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 5:10 hours, implying an average day-over-day increase of 10.0 minutes.

The shortest day of the month is May 1 with 18:51 hours of daylight; the longest day is May 31 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.

May is in polar day from May 18 onward.

Daily Hours of Daylight and Twilight in May

The number of hours during which the Sun is visible (black line), with various degrees of daylight, twilight, and night, indicated by the color bands. From bottom (most yellow) to top (most gray): full daylight, solar twilight (Sun is visible but less than 6° from the horizon), civil twilight (Sun is not visible but is less than 6° below the horizon), nautical twilight (Sun is between 6° and 12° below the horizon), astronomical twilight (Sun is between 12° and 18° below the horizon), and full night.

The earliest sunrise is at 1:03am on May 17; the latest sunset is at 12:18am on May 16; the latest sunrise is at 3:19am on May 1; the earliest sunset is at 10:09pm on May 1.

Daylight savings time is observed in 2012 but it neither starts nor ends in May, so the entire month is in daylight time.

Daily Sunrise & Sunset with Twilight and Daylight Savings Time in May

The solar day over the course of the year 2012 . From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (solar, civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray. The transitions to and from daylight savings time are indicated by the "DST" labels.

Clouds

The median cloud cover is 87% (mostly cloudy) and does not vary substantially over the course of the month.

Median Cloud Cover in May

The median daily cloud cover (black line) with percentile bands (inner band from 40th to 60th percentile, outer band from 25th to 75th percentile).

On May 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 52% of the time.

Cloud Cover Types in May

The fraction of time spent in each of the five sky cover categories. From top (most blue) to bottom (most gray), the categories are clear, mostly clear, partly cloudy, mostly cloudy, and overcast. Pink indicates missing data. Outside of the United States clear skies are often reported ambiguously, leading them to be lumped in with the missing data.

Precipitation

The average probability that some form of precipitation will be observed in a given day is 68%, with little variation over the course of the month.

Probability of Precipitation at Some Point in the Day in May

The fraction of days in which various types of precipitation are observed. If more than one type of precipitation is reported in a given day, the more severe precipitation is counted. For example, if light rain is observed in the same day as a thunderstorm, that day counts towards the thunderstorm totals. The order of severity is from the top down in this graph, with the most severe at the bottom.

Throughout May, the most common forms of precipitation are moderate rain, moderate snow, light rain, and light snow.

Moderate rain is the most severe precipitation observed during 43% of those days with precipitation. It is most likely around May 31, when it is observed during 36% of all days.

Moderate snow is the most severe precipitation observed during 22% of those days with precipitation. It is most likely around May 1, when it is observed during 24% of all days.

Light rain is the most severe precipitation observed during 18% of those days with precipitation. It is most likely around May 23, when it is observed during 14% of all days.

Light snow is the most severe precipitation observed during 13% of those days with precipitation. It is most likely around May 1, when it is observed during 12% of all days.

Types of Precipitation Throughout May

Relative frequency of various types of precipitation over the course of a typical May.

Snow

The likelihood of snow falling is highest around May 1, occurring in 36% of days.

Probability of Snow Fall Being Reported in a Given Day in May

Probability that snow will be reported at least once in a given day.

Either snow rarely accumulates at this location in May or snow depth measurements are unavailable or unreliable.

Humidity

The relative humidity typically ranges from 55% (mildly humid) to 89% (very humid) over the course of a typical May, 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 May 1, rising above 83% (humid) three days out of four.

Relative Humidity in May

The average daily high (blue) and low (brown) relative humidity with percentile bands (inner bands from 25th to 75th percentile, outer bands from 10th to 90th percentile).

Dew Point

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 May, the dew point typically varies from 25°F (dry) to 39°F (dry) and is rarely below 16°F (dry) or above 46°F (dry).

Dew Point in May

The daily average low (blue) and high (red) dew point with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).

Wind

Over the course of May typical wind speeds vary from 1 mph to 15 mph (calm to moderate breeze), rarely exceeding 25 mph (strong breeze).

The highest average wind speed of 9 mph (gentle breeze) occurs around May 31, at which time the average daily maximum wind speed is 15 mph (moderate breeze).

The lowest average wind speed of 8 mph (gentle breeze) occurs around May 10, at which time the average daily maximum wind speed is 14 mph (moderate breeze).

Wind Speed in May

The average daily minimum (red), maximum (green), and average (black) wind speed with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).
The wind is most often out of the south (29% of the time), south west (15% of the time), north (11% of the time), and north east (11% of the time). The wind is least often out of the north west (2% of the time), south east (3% of the time), and east (5% of the time).

Wind Directions in May

The fraction of time spent with the wind blowing from the various directions over the entire year. Values do not sum to 100% because the wind direction is undefined when the wind speed is zero.

Fraction of Time Spent with Various Wind Directions in May

The fraction of time spent with the wind blowing from the various directions on a daily basis. Stacked values do not always sum to 100% because the wind direction is undefined when the wind speed is zero.