Spring - or rather thermal spring - could be arriving to Finland as early as this week in southern and western areas.

Thermal spring is defined as the period when temperatures remain above zero degrees (but below 10 degrees) Celsius throughout the day and night, a seasonal period that usually lasts six to nine weeks.

According to the Finnish Meteorological Institute the thermal spring of 2012 in the southern capital region started on March 10, while in central and eastern areas it started a month later.

The following year was also unusual. In 2013 thermal spring was recorded across most of the country as having started at roughly the same time - around April 10 - and in Lapland only shortly afterwards.

In the south of Finland thermal spring generally starts around March 24th.