I don't agree with the current meme that the Solstice is the start of summer the season; clearly it's already part-way through. One giveaway is that this is Mid-summer's Day and Night.
Another is to look-around at what is happening, has happened, in the natural world: the spring flowers have gone, the trees are in full leaf; spring has been over for at least some weeks.
This error reflects the modern mind. We are happy to live by astronomical observations of a pretty advanced kind; because the solstices and equinoxes could neither be detected nor predicted until the later 100s AD. It needs The Authorities and Instruments to tell us about such matters (with any degree of precision).
Yet we are ignorant and uninterested and mistrustful of things we can actually observe for ourselves - like looking at flowers and trees; we have no faith in our own personal experiences.
Also, the error is revealing of our inability to perceive that seasons are not of equal length, nor do they occur at the same times in all places, nor are they at exactly the same time each year.
All of this we could know for ourselves; yet there is a very modern desire to conflate astronomy, geography and annual variation under one, top-down, officially dictated-in-advance date.
How characteristic this is of our mainstream current weaknesses, credulity, passivity, shallowness.
Midsummer is quite something up here in the far North. If not land of the midnight sun; we are land of the midnight "Nautical Twilight"... I was up with a migraine a couple of nights ago; and I heard the birds' dawn chorus starting at 03:20 - although the sun didn't officially rise for another hour-plus.