The year 2005 will be remembered as an unusually warm year in the whole of Finland. As shown by the statistics compiled for each season, climate change is visible in Finland, too.
When analysing the year's temperature statistics, Anneli Nordlund, senior meteorologist at the Climate Services of the Finnish Meteorological Institute, mentions especially Northern Finland:
"In the North, all months of the year, except March, were warmer than average. The highest one-day temperature was also measured in Lapland: the warmest day of the summer, 30.8° C, was recorded in Sevettijärvi, Inari, on 9 July," says Anneli Nordlund.
Temperatures did not go below -40° C at any point during the year. The lowest temperature, -36.5° C was measured on 29 January in Naruska, Salla. Nordlund says that, on average, temperatures do not fall below -40° C in one out of four winters.
The sunny March with its low precipitation was the only month of the year that was clearly colder than average in the whole of Finland. In contrast, January and November were exceptionally mild months.
Thermal summer (when the daily mean temperature is above 10° C) continued in Southern Finland well into October. Although thermal winter (daily mean temperature below 0° C) did not start until 16 December on the Åland Islands, it started one month earlier, or at a fairly typical time, on Hanko Peninsula and in Vantaa.
"2005 is another link in the series of warmer years, pulling the long-term mean temperature upwards. The view that the effects of climate change can be seen during all seasons in Finland, too, has gained ground since the year 2000."
August was the rainiest month of the year. Anneli Nordlund is sorry for the organisers of the World Championships in Athletics. "Sometimes there may be heavy rains on several days in a row in July and August. The week of the athletics games was annoying for a meteorologist, too, because the next week was very sunny."
Helsinki-Testbed, the denser weather observation network, was in test use during the championships games, too, and provided interesting information. "The organisers' decision to interrupt the event is easy to understand when you hear that the downpour - similar to those in the tropics - lashed 1.5 million litres of water on the Stadium area in one evening," Nordlund relates.
The greatest daily precipitation, 74 mm, was measured in Vilppula on 6 August. The greatest monthly precipitation, 211 mm, was measured in August in Nupuri, Espoo. "When the precipitation of a summer month exceeds 200 mm, it's worth an exclamation mark," Anneli Nordlund points out.
People often contact the Meteorological Institute to report even heavier rainfalls. "However, statistics must be based only on official measurement points. By using weather radars, we can also confirm higher precipitation figures, such as the well over 100 mm that came down one night in mid-June in Multia," Nordlund explains.
In early 2005, Northern Finland had a normal snow cover; in some areas the cover was even thicker than average. A highly unusual feature was the simultaneous lack of snow on the ground in the southern and western parts of the country.
"Since the winter of 1988-1989, the snow cover has become thinner south of Salpausselkä Ridge, in the southwest of Pirkanmaa, in Häme and Varsinais-Suomi and in the low-lying areas of Ostrobothnia. The difference is a good ten centimetres. Snow volumes in what is known as 'Snow Finland' have remained unchanged."
More rainy days than before were measured throughout Finland in winter 2005. For instance in January, there were 14 rainy days in Helsinki (the mean being five), and 12 in Jyväskylä (the mean being two). Lapland, where the mean is under one, had rain on four days in January.
In 2005, windstorms were recorded on 25 days, while the long-term average is 24. Anneli Nordlund says that not a single violent windstorm occurred during the year. "That's something to be satisfied about! People have become more aware of storms, and after some years that had been even calmer, many may have felt that the number of storms was unusually high," Nordlund muses.
For Nordlund, the most memorable event occurred in early January when the water level in the Gulf of Finland had been rising for 10 hours and it seemed that the sea might soon drench the Market Square in Helsinki, threatening even the Presidential Palace.
"A strong wind had been blowing from the southwest for a long time, and as the heaving water masses of the Baltic Sea moved in the right way, great volumes of water pushed all the way to the edges of the Gulf of Finland," Nordlund describes the background. Thanks to marine researchers, (at least some) precautions could be taken against flooding.
The Meteorological Institute received 65 reports of trombs - a record number. "Awareness of trombs has increased, which certainly affects the number of observations. But a remarkable number of trombs did occur last summer, owing to highly favourable weather conditions," Anneli Nordlund recognises.
In summer the number of thunderstorm days was normal, but the number of lightning strokes was merely half of the average figure. Since trombs and lightning rarely occur together, the connection between these two will certainly be studied more. Nordlund points out that trombs are a challenging object of study; not even weather radars can detect them.