For various reasons (please specify in the solution) the date varies from year to year, but (good news!) it is fully predictable.
Please describe how to find the dates of
Solstices and Equinoxes in this century and for that matter for any year, but list them for this century, to allow comparison to published lists, specifying the name and location
of your choice, Northern or Southern Hemisphere and the Time Zone.
Default: Paris, France.