World Shortest Day 2024. So, what is the winter solstice and why does it happen? The actual moment of the solstice in 2024 will occur at 9.21am gmt in the uk, but most people concentrate on the whole solstice day, which has been recognised by holidays and festivals in many cultures around the world.

Solstices come twice a year. As an astronomical occurrence, it marks the beginning of winter in the northern hemisphere and brings the shortest day and longest night of the year.