Average Weather in Helsinki Finland
In Helsinki, the temperature typically varies from 17°F to 71°F over the course of the year, and is rarely below -3°F or above 79°F.
The warm season lasts for 3.0 months, from June 3 to September 4, with an average daily high temperature above 62°F. The hottest day of the year is July 22, with an average high of 71°F and low of 55°F.
The cold season lasts for 3.8 months, from November 26 to March 20, with an average daily high temperature below 36°F. The coldest day of the year is February 7, with an average low of 17°F and high of 27°F.
Average High and Low Temperature
The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.
Average Hourly Temperature
The length of the day in Helsinki varies extremely over the course of the year. In 2017, the shortest day is December 21, with 5 hours, 49 minutes of daylight; the longest day is June 21, with 18 hours, 56 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 3:53 AM on June 19, and the latest sunrise is 5 hours, 32 minutes later at 9:25 AM on December 27. The earliest sunset is at 3:11 PM on December 16, and the latest sunset is 7 hours, 39 minutes later at 10:50 PM on June 23.
Daylight saving time (DST) is observed in Helsinki during 2017, starting in the spring on March 26, lasting 7.1 months, and ending in the fall on October 29.
Sunrise & Sunset with Twilight and Daylight Saving Time
In Helsinki, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.
The clearer part of the year in Helsinki begins around April 22 and lasts for 5.6 months, ending around October 10. On July 18, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 59% of the time, and overcast or mostly cloudy 41% of the time.
The cloudier part of the year begins around October 10 and lasts for 6.4 months, ending around April 22. On January 23, the cloudiest day of the year, the sky is overcast or mostly cloudy 75% of the time, and clear, mostly clear, or partly cloudy 25% of the time.
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Helsinki varies throughout the year.
The wetter season lasts 7.3 months, from June 15 to January 24, with a greater than 25% chance of a given day being a wet day. The chance of a wet day peaks at 32% on November 21.
The drier season lasts 4.7 months, from January 24 to June 15. The smallest chance of a wet day is 17% on February 28.
Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation in Helsinki changes throughout the year.
Rain alone is the most common for 11 months, from February 15 to January 17. The highest chance of a day with rain alone is 30% on October 21.
Snow alone is the most common for 4.1 weeks, from January 17 to February 15. The highest chance of a day with snow alone is 10% on January 26.
Daily Chance of Precipitation
To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day in the year. Helsinki experiences some seasonal variation in monthly rainfall.
Rain falls throughout the year in Helsinki. The most rain falls during the 31 days centered around October 12, with an average total accumulation of 2.2 inches.
The least rain falls around February 18, with and average total accumulation of 0.5 inches.
Average Monthly Rainfall
We report snowfall in liquid-equivalent terms. The actual depth of new snowfall is typically between 5 and 10 times the liquid-equivalent amount, assuming the ground is frozen. Colder, drier snow tends to be on the higher end of that range and warmer, wetter snow on the lower end.
As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day in the year. Helsinki experiences some seasonal variation in monthly liquid-equivalent snowfall.
The snowy period of the year lasts for 5.5 months, from October 30 to April 16, with a sliding 31-day liquid-equivalent snowfall of at least 0.1 inches. The most snow falls during the 31 days centered around January 23, with an average total liquid-equivalent accumulation of 0.6 inches.
The snowless period of the year lasts for 6.5 months, from April 16 to October 30. The least snow falls around July 30, with an average total liquid-equivalent accumulation of 0.0 inches.
Average Liquid-Equivalent Monthly Snowfall
We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.
The perceived humidity level in Helsinki, as measured by the percentage of time in which the humidity comfort level is muggy, oppressive, or miserable, does not vary significantly over the course of the year, staying within 2% of 2% throughout.
Humidity Comfort Levels
This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.
The average hourly wind speed in Helsinki experiences mildly seasonal variation over the course of the year.
The windier part of the year lasts for 5.7 months, from September 16 to March 8, with average wind speeds of more than 4.9 miles per hour. The windiest day of the year is December 13, with an average hourly wind speed of 6.1 miles per hour.
The calmer time of year lasts for 6.3 months, from March 8 to September 16. The calmest day of the year is July 3, with an average hourly wind speed of 3.8 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in Helsinki varies throughout the year.
The wind is most often from the south for 2.1 months, from January 26 to March 29 and for 1.3 months, from November 3 to December 11, with a peak percentage of 35% on November 25. The wind is most often from the west for 7.1 months, from March 29 to November 3 and for 1.5 months, from December 11 to January 26, with a peak percentage of 40% on June 3.
Helsinki is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.
The average water temperature experiences significant seasonal variation over the course of the year.
The time of year with warmer water lasts for 2.6 months, from June 30 to September 18, with an average temperature above 57°F. The day of the year with the warmest water is August 5, with an average temperature of 63°F.
The time of year with cooler water lasts for 4.5 months, from December 17 to May 2, with an average temperature below 39°F. The day of the year with the coolest water is March 1, with an average temperature of 32°F.
Average Water Temperature
This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.
The average daily incident shortwave solar energy experiences very significant seasonal variation over the course of the year.
The brighter period of the year lasts for 3.2 months, from May 4 to August 10, with an average daily incident shortwave energy per square meter above 5.0 kWh. The brightest day of the year is July 2, with an average of 6.3 kWh.
The darker period of the year lasts for 4.5 months, from October 14 to February 27, with an average daily incident shortwave energy per square meter below 1.4 kWh. The darkest day of the year is December 21, with an average of 0.2 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Helsinki are 60.170 deg latitude, 24.935 deg longitude, and 0 ft elevation.
The topography within 2 miles of Helsinki contains only modest variations in elevation, with a maximum elevation change of 148 feet, and an average elevation above sea level of 36 feet. Within 10 miles also contains only modest variations in elevation (253 feet). Within 50 miles contains significant variations in elevation (607 feet).
The area within 2 miles of Helsinki is covered by artificial surfaces (65%) and water (30%), within 10 miles by water (47%) and artificial surfaces (40%), and within 50 miles by water (49%) and trees (32%).
This report illustrates the typical weather in Helsinki, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.
Temperature and Dew Point
There are 2 weather stations near enough to contribute to our estimation of the temperature and dew point in Helsinki.
For each station, the records are corrected for the elevation difference between that station and Helsinki according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.
The estimated value at Helsinki is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Helsinki and a given station.
All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Tables of the Sun, Moon and Planets , by Jean Meeus.
All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.
Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.
Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.
Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .
Time zones for aiports and weather stations are provided by AskGeo.com .