When Is Summer 2024 Start.  — summer begins with the solstice on thursday, june 20, 2024, marking the astronomical first day of summer in the northern hemisphere.  — astronomical summer officially arrives in the northern hemisphere — amidst a heat wave — at 4:51 p.m.

 — with that comes the summer solstice, the day with the most amount of sunlight.  — when does summer start in 2024?