Virtually all of Finland lies between latitudes 60°N and 70°N, but the Gulf Stream and the prevalence of warm westerly winds make the climate several degrees warmer than elsewhere at the same latitude. Summers are short and mild, and the days are long. In June and July only a 2-3 hour period of twilight separates sunset from sunrise. In the extreme north the sun does not set for 73 days during the mid-summer period. Precipitation, averaging 63cm (25 inches) annually, is distributed over all seasons. Winters are long and cold. Snow is possible from October through April, with January through March having the heaviest accumulations. Temperatures may vary from north to south, as does the snow coverage from one winter to the next.
Despite Helsinkiâ€™s location on the Gulf of Finland, the humidity is low. The cityâ€™s average temperature is +5°C (42°F). February and July mean temperatures are -5°C (23°F) and +17°C (63°F) respectively. Average temperatures in Lapland are -12°C (10°F) in January and +17°C (63°F) in July.