Spring Equinox 2024 In Usa. On march 19, the vernal equinox will see spring come to the northern hemisphere as the sun reaches the spot where the ecliptic and celestial equator cross each other. But why does the day mark the start of spring and why only in the northern hemisphere?.

Here are the equinox and solstice dates—plus, answers to common questions about the seasons of the year in north america. The northern hemisphere’s spring — or vernal — equinox can land between march 19 and 21, depending on the year.