The sportlov usually lasts for one week and, depending on where you live in Sweden, comes as early as February 11th-17th or as late as the week of March 4th-10th.
The vacation dates back to the Second World War after a recommendation by the government-run energy commission (bränslekommissionen) which stated in 1940 that Sweden could save fuel by not having to heat up the country's schools for a week during one of the coldest months of the year.
It was initially named kokslov (named after the high-carbon content fuel coke), but eventually changed its name to instead match the winter sports activities on offer for the children on vacation.
In the 1950s, the country's public health services noted that February (popularly referred to also as vabruari) was the peak month for Swedish children catching the flu or the winter vomiting virus, and by keeping them away from the schools for at least one week, the spreading of such illnesses reduced drastically. The Swedish government then decided to retain the vacation.
Since then, the sportlov, which combines the two words sport and lov (which literally translate into 'sports' and 'permission') has become a Swedish institution dedicated to children's sports and being active.
The word lov is the term commonly used to refer to Swedish school vacations: sommarlov, jullov, and påsklov (summer vacation, Christmas vacation and easter vacation), which means permission. According to the Language Council of Sweden, the term's application dates back to the 1600s and means that a student has permission to miss school.
Watch a Stockholmer explain why lov is her favourite Swedish word in the video below: