Summer Solstice 2024. 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. Astronomical summer officially arrives in the northern hemisphere — amidst a heat wave — at 4:51 p.m.
It is the longest day of the year that marks the. The summer solstice, which is when the sun reaches the most northerly point in the sky, is set to occur tonight at 21:50 bst/22:50 cest.