The seasons can be distinguished by monitoring changes in the average temperature. The seasons change, when the daily average temperature surpasses a certain temperature. As a result, individual cold days during autumn are not yet called winter. The change between seasons can often only be seen afterwards. 

The number of seasons experienced in a certain area is a direct result of the area's climate. In Finland, we have four distinct seasons. 

Winter is the coldest season of the year. During winter, the average daily temperature stays below zero degrees Celsius. Winter is the longest season in many parts of Finland. In Lapland, it can take up over half of each year. The southern winter begins towards the end of November and lasts approximately four months.

Winter is also much harsher in northern parts of the nation than it is in its southern parts. In addition, the northernmost parts of Finland experience the dark season of the polar night during the winter.

Autumn and spring are transitional seasons that occur between winter and summer. During both of these seasons, the average daily temperature is located between 0 and +10 degrees Celsius. In most regions of Finland, spring begins in April, but in the northernmost parts of the nation it often begins in May. The Finnish spring lasts for 1,5–2 months. The Finnish autumn begins in the middle of September in the south, and towards the August in the north. The Finnish autumn lasts for 2–2,5 months. The autumn foliage of trees and shrubs brings a splash of color to the otherwise rainy and darkening season.

Summer is the warmest month. During the summer, the average daily temperature stays above +10 degrees Celsius. It lasts for approximately four months in the southern regions of Finland, but in Lapland the summer is much shorter, lasting for only two months.

The growing season of plants begins when the daily average temperature begins to stay above +5 degrees Celsius. This is an important time for plant growth and agriculture. The growing season begins during spring and lasts all the way to autumn. The difference between the lengths of growing seasons in Northern and Southern Finland is reduced by the amount of light received in northern areas of the nation due to the midnight sun. 


The four seasons.