In the UK, the summer solstice is the longest day of the year and also the official start to summer
The date varies between June 20 and June 21, depending on the year.
In 2020 the summer solstice in the United Kingdom is on Saturday, 20 June.
The word solstice, from the Latin solstitium means sun-stopping. The point on the horizon where the sun appears to rise and set, stops and reverses direction after this day. On the solstice, the sun does not rise precisely in the east, but rises to the north of east and sets to the north of west, meaning it’s visible in the sky for a longer period of time.
Although the June solstice marks the first day of astronomical summer, if you refer to the meteorological definition of seasons, the solstice is actually midsummer.