The summer solstice occurs during the hemisphere's summer . In the Northern Hemisphere, this is the June solstice (20 or 21 June) and in the Southern Hemisphere, this is the December solstice (21 or 22 December). Since prehistory, the summer solstice has been a significant time of year in many cultures, and has been marked by festivals and rituals. The 2025 summer solstice takes place on June 20, heralding the onset of astronomical summer and the longest day of the year. The summer solstice marks the longest day in the Northern Hemisphere and the start of astronomical summer , while the Southern Hemisphere experiences its shortest day and the beginning of winter. 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.
