Two thousand brave souls took to the icy waters of Hobart’s River Derwent on Thursday morning wearing nothing but an orange swimming cap, enduring a stark-naked sunrise swim to mark the end of the longest night of the year across Australia and the Southern Hemisphere.

The Southern Hemisphere’s winter solstice occurred last night, marking the moment the Southern Hemisphere reached its furthest tilt away from the sun. This made it the longest night of the year across Australia.

Video: Orientation of Earth relative to the Sun at the time of the Southern Hemisphere’s winter solstice, with the Sun positioned directly above the Tropic of Cancer and the sun reaching its lowest point in the Southern Hemisphere’s sky. Source: NASA Scientific Visualization Studio

Being Australia’s southernmost capital city, Hobart experienced a whopping 14 hours and 59 minutes between sunset on Wednesday and sunrise on Thursday. The year’s longest night allowed temperatures to drop as low as 2.8ºC in Hobart early on Thursday morning.

For most people, a night this long and cold is nothing more than a perfect excuse to pull up the doona and sleep in. But for 2000 bold (and some bald) bathers, it was an unmissable opportunity to take part in Hobart’s annual Nude Solstice Swim.

Image: Swimmers plunge into the River Derwent in Hobart on Thursday morning. Source: AAP

The Nude Solstice Swim marks the end of Tasmania’s Dark Mofo festival, which is now in its 10th year and growing in popularity. The Nude Solstice Swim is in such high demand that organisers have had to cap entries at 2000 people.

Image: Solstice swimmers gather on Long Beach, Hobart on Thursday morning. Source: AAP

As the sun rose on Thursday morning, the air temperature in Hobart was sitting on 3ºC and the ‘feels like’ temperature was down at -2.1ºC thanks to northwesterly winds averaging 17 km/h. This would have been a fair bit colder than the water temperature in the River Derwent.

Days will now start getting longer in Hobart and the rest of Australia until the longest day and shortest night of 2023 occurs in late December.