The times when the Sun is at its furthest from the celestial equator are called the summer and winter solstices and these occur in mid-summer and mid-winter. The word 'solstice' comes from the Latin solstitium meaning 'Sun stands still' because the apparent movement of the Sun's path north or south stops before changing direction.
This year the Winter Solstice falls on 21st December in the Northern hemisphere. The exact time astronomers would give for the Winter Solstice this year is 23:03 UTC (GMT)... 12 hours from now.
So... Happy Winter Solstice!