1st Day Of Spring 2024 Date. Spring is deemed to start at the vernal equinox (near 20 march) summer at the summer solstice (near 21 june) autumn at the autumn equinox (near 23 september) winter at. There are four astronomical seasons on earth, defined by the movement of the sun in the sky.
Here’s why our seasons roll over on the same date every year. Astronomically speaking, the first day of spring is marked by the spring equinox, which falls on march 19, 20, or 21.