Vernal Equinox 2024 Edt. But why does the day mark the start of spring and why only in the northern hemisphere?. The spring equinox (march 19, 2024) signals the start of spring in the northern hemisphere, the beginning of autumn in the southern hemisphere, and a rare moment of equal night across the.

Pdt (and 03:06 gmt on wednesday) the sun will cross the celestial equator traveling north, marking the vernal equinox in the northern. Many know it as the first day of spring, but it is also called the spring equinox or vernal equinox.