What is the first day of summer?
In the USA, the first day of summer is June 21 or June 22
depending on the time zone. However, this is not the case
throughout the northern hemisphere, as many countries officially
start their summer on 1 June.
Similarly, for the southern hemisphere the dates vary according
to the country. The summer solstice is December 21 or 22 depending
on the time zone, but in Australia and New Zealand, summer starts
on 1 December.