Re: Who cares...
" In the UK, 20th June 2016 was the start of summer astronomically speaking."
Could you explain what you mean by that?
Fwiw, British Summer Time (BST) starts on the last Sunday of March and ends on the last Sunday of October.
June 20th, aka the summer solstice, is generally regarded as mid-summer and, by no coincidence, falls roughly mid-way between those two dates.