Today, Thursday December 22, will be the longest day of the year in Australia thanks to this morning's summer solstice.

The summer solstice marks the moment Earth’s south pole reaches its furthest tilt towards from the sun, which causes the year’s longest amount of time between sunrise and sunset.

This year’s Southern Hemisphere summer solstice (winter solstice for the Northern Hemisphere) occurred at 8:48 am AEDT on Thursday, December 22. The satellite image below shows what the view from space looked like near the time of the solstice.

Image: Satellite image captured by the Himawari-9 satellite around the time of this year’s summer solstice.

In the image above, the sharp angle of the solar terminator (line between day and night) relative to the horizon is a clear sign of the summer solstice. In three months, on the date of the next equinox, the solar terminator will be running straight from north-to-south, sitting perpendicular to the equator.

The table below shows how long today will be in each Australian capital city based on daylight hours.

Days will now start getting shorter and nights will become longer across Australia. This trend will continue for about six months, until we reach the shortest day of 2023 on the winter solstice in late June.