Finland uses Eastern European Time (EET) during the winter as standard time and Eastern European Summer Time (EEST) during the summer as daylight saving time. EET is two hours ahead of coordinated universal time (UTC+02:00) and EEST is three hours ahead of coordinated universal time (UTC+03:00). Finland adopted EET on 30 April 1921, and has observed daylight saving time in its current alignment since 1981 by advancing the clock forward one hour at 03:00 EET on the last Sunday in March and back at 04:00 EET on the last Sunday in October, doing so an hour earlier for the first two years.
Before the 19th century, each locality followed its own solar time, which meant the time between the western and easternmost localities of Finland differed by thirty minutes. In the 19th century, a single time zone across Finland was needed to coordinate scheduling for the newly invented railway and telegraph. In 1862, the mean time 1:39:49.2 ahead of UT was adopted for the railway. Two separate, unsuccessful proposals for a standard time zone were made by the Diet of Finland in 1888 and 1897, when Finland was an autonomous duchy of the Russian Empire. On 30 April 1921, the newly independent government officially adopted the time zone UTC+02:00, known as Eastern European Time. Daylight saving time was first attempted in 1942, but abandoned as not useful. It was introduced again in 1981, so that Finland's time zone could always be aligned with neighbouring countries. In 2017, the Finnish parliament voted in favour of proposals calling on the European Union to consider abolishing daylight saving time.
Finland's time zone is maintained by the VTT Technical Research Centre of Finland and the Centre for Metrology and Accreditation. Using atomic clocks, they make sure the official timekeeping devices in Finland do not fall behind. Finland's high latitude means that in summer the nights are short, and daylight saving time has no impact on the population. Northernmost Finland is within the Arctic circle and has a polar night lasting 51 days and a polar day lasting 73 days, whilst the southernmost localities of Finland experience less than six hours of daylight in winter and an average of 20 hours of daylight in summer. The country uses the 24 hour clock notation.
History
Before the 19th century, there was no need for a single time zone across Finland, and each locality followed its own solar time. This meant that if it was 12:00 in Helsinki, the local times in other localities would range from 11:40.02 in Mariehamn, Åland, to 12:10.53 in Kuopio, North Savo. The railway required more precise timetables than earlier means of transport, such as sailing ships and stage-coaches. The telegraph, which allowed near real-time communication, also made it inconvenient for each location to observe its own solar time.
The first railway line in Finland (the Hämeenlinna–Helsinki railway) was inaugurated in 1862. Its timetables were noted in a common mean time, measured at the Helsinki University Observatory from the mean time of UTC+01:39:49.2, known as "Helsinki time". A ball was released at noon and its falling was noted optically at the railway station and the clock adjusted accordingly. If it was raining, which would prevent the ball from being seen from that far away, noon would additionally be announced by a shot from a cannon. The correct time was relayed to the other stations via electrical telegraph, which had been introduced in Finland in 1854. On the Riihimäki–Saint Petersburg railway, inaugurated in 1870, Helsinki time was used as far as Kaipiainen, just east of Kouvola. In 1882, clock synchronisations to Helsinki time by telephone were arranged between the Finnish Meteorological Institute and Sweden's National Meteorological Institute in order to conveniently conduct geomagnetic measurements.
The International Meridian Conference held in Washington, D.C. in October 1884 divided the world into 24 meridians, each one covering 15 degrees of longitude. Each meridian had an hourly offset from Greenwich Mean Time in the United Kingdom (which was agreed to be the prime meridian at the conference), ranging from GMT−12:00 to the west to GMT+12:00 to the east. However this was not immediately implemented in most countries, including Finland. In October 1893, most of the railways in Europe adopted the offsets GMT (also named Western European Time), GMT+01:00 (Middle European Time or Central European Time) and GMT+02:00 (Eastern European Time). The implementation of this was overseen by the American Railway Association. Between 1893 and 1895, several countries in Europe adopted standard times that corresponded with one of these three time zones, but Finland did not.