Solar New Year is the beginning of solar calendar year. The event is celebrated by numerous cultures in various ways at diverse dates. The most common bases chosen to begin a new calendar year are the winter solstice, summer solstice, the spring equinox and the autumnal equinox. South and South-east Asian solar calendars are more formally linked to astronomical events.

Some of the more widely known solar new year celebrations include:

• Enkutatash (Ethiopian calendar): about ten days before the autumnal equinox
• January 1 in the Gregorian and Julian calendars (same number, different days): at present^[a] about twelve and twenty-five days respectively after the northern winter solstice.
• Iranian New Year (Nowruz) : precisely the northern spring equinox
• The various solar new years celebrated in South/SE Asia, whose new year is determined by the position of the Sun relative to the constellation of Aries,^[1] such as
  • Cambodian New Year: about six or seven days before the northern spring equinox
  • Tamil New Year (Puthandu): about 24 or 25 days after the northern spring equinox
  • Vaisakhi: about 24 or 25 days after the northern spring equinox
  • Pohela Boishakh (Bengali calendar): about 24 or 25 days after the northern spring equinox