2025 Solstice And Equinox Dates. The june solstice is the longest day of the year in the northern hemisphere and the shortest day in the southern hemisphere. On this date, the day is equal in length to the night.

On the day of the spring (march) equinox, the sun crosses the celestial equator, moving along the ecliptic. The sun shines directly on the equator on the september equinox and the length of day and night is.