First Day Of Summer 2024 Calendar Datev. Thursday, june 20 is the official first day of northern astronomical summer for 2024 — summer solstice — which is the longest day of the year for this half of the planet. 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. Fall starts at the moment when the sun is directly over the equator, going from north to south: