Longest And Shortest Day Of The Year 2024 Usa. It marks the shortest day and longest night of the year and the first day of the winter in. The first day of winter in the northern hemisphere is marked by the winter solstice, which occurs on saturday, december 21, 2024, at 4:21 a.m.

In the southern hemisphere, june 20 is the shortest day of the year. 21 or 22 every year in the northern hemisphere.