The southern hemisphere's winter solstice occurs in Australia on Thursday, marking the shortest day of the year across the country.

Throughout each year, Earth's poles are constantly pointing further towards and away from the Sun as our planet completes its annual orbit around the Sun. This change in tilt relative to the Sun produces our four seasons: summer, autumn, winter and spring.

Our planet's south pole reaches its furthest tilt away from the Sun in late June each year, on a date known as the winter solstice in the southern hemisphere. At this point in time, the Sun reaches its northernmost point in our sky, causing those living south of the equator to experience their shortest day of the year.

This year's winter solstice in Australia occurs at 8:17pm Australian Eastern Standard Time on Thursday, June 21st. As a result, Thursday will be the shortest of the year across the country.

From Friday, days will gradually increase in length across Australia until the south pole reaches it furthest tilt towards the sun. This moment will mark the longest day of the year in Australia, on the southern hemisphere's summer solstice in late December.