March Equinox 2025. The march equinox marks the first day of spring for anybody living in the northern hemisphere, and the first day of autumn for anybody living in the southern hemisphere. When is the first day of spring 2025?
September 22, 2025 at 5:43 am pdt : The spring equinox (march 19, 2025) signals the start of spring in the northern hemisphere, the beginning of autumn in the southern hemisphere, and a rare moment.