The southern hemisphere’s summer solstice will occur this weekend, marking the longest day and shortest night of the year in Australia.

The summer solstice occurs when either of Earth’s poles reach their greatest tilt towards the Sun. In the southern hemisphere, the summer solstice occurs in late December and this year it falls on December 21.

The date of the summer solstice marks the longest day of the year based on the amount of time between sunrise and sunset.

Image: Daily forecast featuring sunrise & sunset times on the Weatherzone app for Melbourne, Vic, on December 20. Valid on December 17, 2024.

This Saturday, December 21, the daylength will be about 14 hours and 25 minutes in Sydney and about half an hour longer than that in Melbourne.

Daylengths for the rest of Australia’s capital cities will range from around 12 hours and 52 minutes to 15 hours and 22 minutes on the summer solstice this weekend.

Image: Approximate daylengths in Australia’s capital cities on the date of the 2024 summer solstice.

Following Saturday’s solstice, days will start to get shorter and nights will become longer across Australia. This trend will continue for the following six months until the date of the winter solstice in late-June 2025.