- https://en.wikipedia.org/wiki/December_solstice – 2023-12-22 (i.e. today) – start of winter – days will be longer and longer until June solstice
- https://en.wikipedia.org/wiki/June_solstice – 2023-06-20 – start of summer
- https://en.wikipedia.org/wiki/March_equinox – 2023-03-20 – start of spring
- https://en.wikipedia.org/wiki/September_equinox – 2023-09-22 – start of autumn