The Sun is at its northernmost point in the sky on the winter solstice.
Source: Robert Price, Bethanga, Victoria
Wednesday 21 June was the shortest day of the year, also known as the winter solstice.
More correctly, it was the day on which the solstice fell, at 10:26pm AEST.
Solstice means ‘Sun stands still’. Although the Sun never stops moving from east to west across the sky, it does stop moving in a south-north direction. Our winter solstice is the precise moment at which the Sun reaches its northernmost point in the sky, stops, then starts moving south again.
After the solstice, the Sun starts rising higher in the sky, and the points on the horizon where the Sun rises or sets start moving south.
Of course the Sun is not really moving south and north. Its apparent movement is a result of the Earth’s tilted axis moving around the Sun. On the winter solstice the axis is tilted away from the Sun, the Sun rises lowest in the sky and sunlight is the most spread out across the ground.
The day on which the solstice falls is the shortest day of the year, but not the day with the latest sunrise or the earliest sunset. This is because Sun time does not keep exactly in step with clock time.
Around the winter solstice, Sun time is going slightly slower than clock time, so sunrise is getting later relative to the clock. The longer day will not be large enough to offset this for just over a week, so sunrise will keep getting later until then. Similarly the earliest sunset was just over a week ago.
Nor is the solstice the coldest day of the year. Although the ground will start receiving more sunlight, it will keep cooling for about another month. At that point the sunlight will be strong enough for the earth to start warming up again.