The Northern Hemisphere’s spring — or vernal — equinox can land between March 19 and 21, depending on the year. Its fall – or autumnal — equinox can land between Sept. 21 and 24.

The spring equinox always falls on March 20 or 21 (and occasionally on March 19 in a leap year). In 2025, the big day is Thursday, March 20.

The vernal equinox marks the start of spring in the Northern Hemisphere — so does that mean this is the only day out of the year when you’ll be able to balance an egg? Or not see your own shadow?