Present climate - 30 year mean values
The main factor influencing Finland's climate is the country's geographical position on high latitudes on the edge of a big continent. Weather in Finland varies greatly depending on the direction from which air flow and moving low and high pressures come at each time.
Finland's climate shows both maritime and continental characteristics
Finland's climate is so-called intermediate climate, combining characteristics of both a maritime and a continental climate. Weather in Finland depends very much on the prevailing wind direction and on how weather disturbances, i.e. low and high pressures, are situated. Finland is located in the zone of prevailing westerly winds on medium latitudes where tropical and polar air masses meet, where weather types vary rapidly particularly in winter. The prevailing air flow in Finland comes from the south-west.
Finland's mean temperature is several degrees higher than in most other continental areas located in the same latitudes. For instance, in comparison with the eastern part of Canada, Greenland and Siberia, the difference in the winter months can be 20-30 degrees. The primary reason for Northern Europe being this warm is the Gulf Stream and its extension, the warm North Atlantic current that transmits warmth from around the equator all the way up to the Arctic Sea. Finland's climate is warmed and balanced also by the Baltic Sea with its bays and numerous inland water bodies.
The annual mean temperature varies from more than +5 degrees in southwestern Finland to a couple of degrees below zero in Northern Lapland. Due to the warming effect of the Arctic Sea, Finland's coldest spot is not located in northernmost Lapland but in the north-western corner of the country.
The coldest time of the year is typically well after perihelion, i.e. in late January, except in maritime islands and coastal regions, where the slower cooling of the sea delays the coldest time until the first or second week of February. The lowest winter temperatures in Lapland and Eastern Finland are -45… -50 degrees, in other parts of the country usually between -35 and -45 degrees, in coastal regions and maritime islands, however, usually -25… -35 degrees. The lowest temperature recorded in the 1900s in Finland's meteorological observing stations was -51.5°C in January 1999 (Pokka, Kittilä, 28.1.1999).
The warmest time of the year occurs, on average, about one month after aphelion, i.e. around 20th July, in the whole of Finland. In continental Finland, the highest summer temperatures reach 32…35 degrees. Near the sea, and in the archipelago, temperatures extremely rarely exceed 30°C. The highest temperature ever recorded in Finland dates back to July 2010: 37.2°C at the Joensuu airport in Liperi.
For more temperature statistics and records, see the website (in Finnish): https://ilmatieteenlaitos.fi/lampotilaennatyksia
The annual amount of precipitation in Finland varies between 500 and 650 millimetres. Lapland has the least precipitation, while inland areas in the southern and central parts of the country get the most downpour.
The spring months see the least precipitation, while the amounts of precipitation increase towards summer so that July-August are typically the rainiest months. In the autumn, the amounts of precipitation begin to decrease again, but days with precipitation are more frequent in the autumn and winter. Usually, the number of days with precipitation per month is lowest in summer, but daily amounts of precipitation are highest in summer rain showers.
For more precipitation statistics and records, see the website (in Finnish): https://ilmatieteenlaitos.fi/sade-ennatyksia
In Central and Northern Lapland, and the Koillismaa District, winter typically lasts for around seven months, and snow stays on the ground for more than six months every year. The number of days with snow cover decreases gradually towards the south and southwest. On the southwestern coast, the ground is covered with snow for a total of 3-4 months a year on average. Snow cover is deepest in late winter, typically in March, but in Lapland, not until April. Quite soon after, the snow begins to melt quickly. Snow is deepest in Lapland, more than 150 cm at most, but in the southern parts of the country, too, snow has been over one metre deep during snowiest winters.
For more snow statistics and records, see the website (in Finnish): https://ilmatieteenlaitos.fi/lumiennatyksia
Cloud cover and sunshine
Finland's sunniest areas are the southwestern sea and coastal areas with an average 1,900 hours of sunshine a year. The number of sunshine hours decreases gradually towards inland and northern areas, so that the eastern part of Lapland has the least sunshine, some 1,300 hours a year.
The cloud cover is abundant in Finland, particularly in the autumn and winter. The number of cloudy days with at least 80% of the sky covered with clouds is usually higher every month than that of days with clear skies (at most 20% of the sky covered by cloud) or partly cloudy days. The number of days with clear skies is highest in May-June, lowest in November-December.