First Day Of Summer 2024 Usa Calendar. This is the longest day of the year and marks the start of summer in the northern hemisphere. Summer begins with the solstice on thursday, june 20, 2024, marking the astronomical first day of summer in the northern hemisphere.

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 day of summer in north america is thursday, june 20, 2024.