This Wednesday, March 20, marked the autumnal equinox in the Southern Hemisphere, meaning nights will now become longer than days in Australia for the next 6 months.

The autumn equinox marks the moment the sun is positioned directly above Earth’s equator, which causes roughly equal amounts of day and night across our planet.

Following this week's equinox, Earth’s South Pole starts to tilt further away from the Sun and the Northern Hemisphere becomes tilted more towards the sun. This change in Earth’s tilt relative to the sun causes nights to become longer than days everywhere south of the equator.

Nights will now be longer than days in Australia for the next six months, until the date of the Southern Hemisphere’s spring equinox in late September.

Halfway between these two equinoxes will be the winter solstice in late June, marking the Southern Hemisphere’s shortest day of the year.

While meteorologists and many countries consider March 1 to be the beginning of autumn, some people use the dates of the equinoxes and solstices to mark the change of seasons. Either way, autumn is now underway in the Southern Hemisphere.