Awakenings 2024 Summer Solstice. Why is this day so.  — solstice—the longest day of the year in the northern hemisphere and the shortest in the southern hemisphere—will occur on thursday, june 20, at 20:50.

 — the summer solstice, occurring on june 21, marks the longest day of the year and signifies the onset of summer in the northern hemisphere. Cross the equator and the situation is reversed.