Monday is the Winter Solstice, meaning it is the shortest day of the entire year. Sydney, Melbourne and Adelaide will all see less than ten hours of sunlight today and tomorrow, whilst Brisbane, and Perth will see under ten and a half. People in Hobart will see a measly nine hours of sun today and tomorrow. Meanwhile, residents in Darwin will bask in a luxurious eleven and a half hours of sunlight. The Winter Solstice occurs due to the tilt of earth's axis. Among other things, this tilt is responsible for the change in seasons. In winter, this tilt means we don't get as much direct sunlight in the Southern Hemisphere, generally making the days gradually cooler. At the same time, the Northern Hemisphere gets plenty of sunlight, and so this period becomes their summer. As we have moved into winter, you may have noticed that the peak of the sun has sunk deeper and deeper into the horizon. This is the sun moving north relative to us. For Australians, the sun will reach its northern-most point in the sky at about 2:38am AEST tomorrow morning. From Tuesday, the days will gradually lengthen. However, the sun will only hang around a minute or so longer each day until we finally reach the longest day, the Summer Solstice in December.