Summer will begin exactly 21 June. Of course, it is about the beginning of the astronomical summer, that is, the day, which is the longest in the whole year. It will last over 16 Hours. In a word, at this time, the so-called summer solstice occurs. The astronomical summer lasts until the fall equinox, which usually occurs around 22 -23 Sept..
We can also say about the beginning of the calendar summer, which is taking place 22 June and lasts until 23 Sept., with the advent of the calendar autumn. There is also another division, which is changeable and concerns more scientific spheres. More specifically, it is about the climate summer. We can only talk about the climate summer at the moment, when the average daily temperature will be above 15 degrees. It turns out, it's not that obvious, that climatic summer will begin with the advent of astronomical summer, because it can be really different.
For children, school holidays will be the most important anyway, which this year begins officially 30 June. So on Monday, right after my last day of going to school for my certificates, or 27 June. But the most important thing is this, to spend the summer safely, not charging to the edge of the law and not being guided by a lack of sense. That everyone would come back safe and sound after the holidays.