Summer Solstice 2025. Summer solstice, the two moments during the year when the path of the sun in the sky is farthest north in the northern hemisphere (june 20 or 21) or farthest south in the southern. The summer solstice is the longest day of the year, meaning the day of the year that has the most hours of sunlight.

The times of the equinoxes mark the beginning of spring and fall. Summer 2025 starts on friday, june 20th in the northern hemisphere, with the first day of summer being the longest daylight day of the year with the earth’s axis having reached.