When Is The Official Day Of Spring 2025. The transition of spring equinox marks the start of the northern hemisphere’s spring, but it is the southern hemisphere’s autumn. Spring will last from march 19 until june 20, when summer officially starts in 2025.

The first day of spring in the uk astronomically occurs on the vernal equinox, 20 march 2025. When is the first day of spring in 2025 happening?