Hi Markku. I suppose your school year is governed by the weather. Our schools start in January and end in December. we don't have severe winters though. I think it's fantastic that the children get the summer off basically. I saw Malta's school term the other day and they have basically 3 months off for summer holidays.
The biggest downside of the over two-month long holiday is that in families with children in first or second grade, there may not be an adult at home to watch over the kids. Kids in school are two old for day care and because workers generally get four weeks of paid holiday in the summer (and one week in the winter season), the eight weeks put together are not enough to cover the ten-week school holiday even if the parents are able to have their holidays with no overlap. That's where grandparents need to help or the kids need to be sent on a camp or something. Some kids may be mature enough to handle spending eight hours on their own at home.
Didn't think of that. I am sure it creates problems.