Sunday’s out-of-nowhere weather event that dropped the couple or so inches of snow Boston needed to make winter history came just in time, because the vernal equinox approaches.

It’s happening this Friday, March 20. And by the way: Friday is the first day of spring.

Equinox is derived from the Latin words aequus (equal) and nox (night). The vernal (or spring) equinox is the first of two equinoxes that happen in March and September every year. On Friday, the first day of spring, at precisely 6:45 p.m., the Sun will cross the celestial equator from south to north; meaning that the Earth will face perpendicular to the Sun’s rays (see: above illustration).

Yes, Boston, winter – the calendar winter, at least – is finally coming to an end. The only downside to all this Friday awesome: if you’re in Boston, you won’t be able to catch a glimpse of the total solar eclipse.

Featured photo by Bill Ilot/CC BY 2.0