Last Day Of Summer 2024 Usa Dates. Starts on tuesday, march 19 at 11:06 pm, and ends on june 20 at 4:51 pm. Astronomically, the last day of summer is sept.

It’s the longest day of the year and follows father’s day and juneteenth, which fall earlier in the same week. This year, the first day of summer, also known as the summer solstice, is thursday, june 20.