This report describes the typical weather at the Turku Airport (Turku, Finland) 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.
Turku has a humid continental climate with warm summers and no dry season. The area within 25 mi of this station is covered by forests (65%), oceans and seas (20%), and croplands (12%).
Over the course of a year, the temperature typically varies from 15°F to 71°F and is rarely below -5°F or above 80°F.
The warm season lasts from May 28 to September 4 with an average daily high temperature above 62°F. The hottest day of the year is July 31, with an average high of 71°F and low of 55°F.
The cold season lasts from November 25 to March 18 with an average daily high temperature below 35°F. The coldest day of the year is February 14, with an average low of 15°F and high of 26°F.
The length of the day varies significantly over the course of the year. The shortest day is December 21 with 5:43 hours of daylight; the longest day is June 20 with 19:02 hours of daylight.
The earliest sunrise is at 4:00am on June 14 and the latest sunset is at 11:05pm on June 27. The latest sunrise is at 9:41am on December 27 and the earliest sunset is at 3:18pm on December 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 ranges from 56% (partly cloudy) to 92% (mostly cloudy). The sky is cloudiest on December 24 and clearest on June 6. The clearer part of the year begins around April 10. The cloudier part of the year begins around September 18.
On June 6, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 57% of the time, and overcast or mostly cloudy 30% of the time.
On December 24, the cloudiest day of the year, the sky is overcast, mostly cloudy, or partly cloudy 75% of the time, and clear or mostly clear 17% of the time.
The probability that precipitation will be observed at this location varies throughout the year. Precipitation is most likely around December 14, occurring in 83% of days. Precipitation is least likely around May 12, occurring in 47% of days.
Over the entire year, 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 33% of those days with precipitation. It is most likely around September 23, when it is observed during 36% of all days.
Moderate snow is the most severe precipitation observed during 29% of those days with precipitation. It is most likely around January 5, when it is observed during 47% of all days.
Light rain is the most severe precipitation observed during 15% of those days with precipitation. It is most likely around May 28, when it is observed during 14% of all days.
Light snow is the most severe precipitation observed during 11% of those days with precipitation. It is most likely around January 21, when it is observed during 17% of all days.
During the warm season, which lasts from May 28 to September 4, there is a 53% 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 (54% of days with precipitation have at worst moderate rain), light rain (23%), and thunderstorms (18%).
During the cold season, which lasts from November 25 to March 18, there is a 77% 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 (54% of days with precipitation have at worst moderate snow), light snow (20%), moderate rain (11%), and heavy snow (6%).
The likelihood of snow falling is highest around January 16, occurring in 69% of days. The season in which it is relatively likely for snow to fall spans from October 30 to April 18.
During peak snow season, accumulation at this location on a given day is about as likely as not. The chances of there being snow on the ground are highest around January 25, occurring 55% of the time. The season in which snow is relatively likely to be on the ground spans from November 13 to April 9.
The snow is typically at its deepest on March 21, with a median depth of 9.8"; the depth exceeds 19.8" only one year out of ten.
The relative humidity typically ranges from 42% (comfortable) to 98% (very humid) over the course of the year, rarely dropping below 25% (dry) and reaching as high as 100% (very humid).
The air is driest around May 15, at which time the relative humidity drops below 51% (mildly humid) three days out of four; it is most humid around November 24, exceeding 98% (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 12°F (dry) to 58°F (comfortable) and is rarely below -8°F (dry) or above 64°F (mildy humid).
The time of the year between June 12 and September 15 is the most comfortable, with dew points that are neither too dry nor too muggy.
Over the course of the year typical wind speeds vary from 1 mph to 13 mph (light air to moderate breeze), rarely exceeding 20 mph (fresh breeze).
The highest average wind speed of 8 mph (gentle breeze) occurs around November 29, at which time the average daily maximum wind speed is 13 mph (moderate breeze).
The lowest average wind speed of 6 mph (light breeze) occurs around August 5, at which time the average daily maximum wind speed is 12 mph (gentle breeze).