Answer: equinoxes

AnswerCrossword Clue
EQUINOXESCertain spring and fall events.
EQUINOXESSeason openers?
EQUINOXESThere are two every year
equinoxesEQUINOX, the time when the sun crosses the equator
equinoxesThe time or date (twice each year) at which the sun crosses the celestial equator, when day and night are of equal length (about September 22 and March 20)