Astronomical
A live countdown to the next equinox or solstice — the four moments that mark the astronomical start of each season.
Earth takes about 365.24 days to orbit the sun — not a clean 365 — so the precise moment of each equinox and solstice drifts later by roughly 6 hours every year, then jumps back after each leap year resets the accumulated drift. That's why these events land anywhere from the 19th to the 23rd of their respective month rather than on one fixed date.
The dates and times below are published astronomical values (consistent with sources like Wikipedia and the IMCCE), not a browser-side approximation — precise second-level equinox/solstice timing requires modeling Earth's actual orbital position, which isn't something worth approximating client-side when accurate reference data exists.
Related
See exactly how daylight hours change across the year.
Sunrise and sunset times for any date and location.
Another live astronomical countdown.