Summer solstice: 2025: Wondering when Summer Solstice

Summer Solstice 2025: Wondering when Summer Solstice 2025 falls? Find out the exact date, time, and why June 20 or 21 marks the longest day of the year with scientific reasons and seasonal significance explained. What is the summer solstice , and when does it happen? The longest day of the year falls on either June 20 or 21 every year in the Northern Hemisphere. A solstice is the day when the sun is at its highest or lowest point in the sky. The summer solstice signals the beginning of astronomical summer and the winter solstice signals the beginning of winter. Perhaps most importantly though, the solstices mark the longest and shortest day of the year. Summer solstice is an annual astronomical phenomenon that brings the longest day of the year.