Winter solstice - Wikipedia
https://en.wikipedia.org/wiki/Winter_solsticeThe winter solstice occurs during the hemisphere's winter. In the Northern Hemisphere, this is the December solstice (usually 21st or 22nd December) and in the Southern Hemisphere, this is the June solstice (usually 20th or 21st of June). Although the winter solstice itself lasts only a moment, the term also refers to the day on which it occurs.
December solstice - Wikipedia
https://en.wikipedia.org/wiki/December_solsticeThe December solstice, also known as the southern solstice, is the solstice that occurs each December – typically on 21 December, but may vary by one day in either direction according to the Gregorian calendar.In the Northern Hemisphere, the December solstice is the winter solstice (the day with the shortest period of daylight), whilst in the Southern Hemisphere it is the …