When Does Summer Start 2024. The first day of summer is also known as the summer solstice, and in 2024 it happens on thursday, june 20 at 4:51 p.m. The first official day of summer is thursday, june 20, 2024.
The period when the clocks are 1 hour ahead is called british summer time (bst). Ct on june 20, according to timeanddate.com.