What Is the Summer Solstice? Summer may feel like it starts when the weather warms up, but the summer solstice is the official start of the season in the Northern Hemisphere. Here are some facts about summer's kickoff. Solstice means “sun standing still” in Latin. The solstice, which typically falls on June 20 or 21, brings the longest day and shortest night of the year. The solstice was an important event in many ancient societies. The astronomical phenomenon occurs when the North Pole is closest to the sun. When the Northern Hemisphere is experiencing summer, it's winter in the Southern Hemisphere. Solstices are thought to be one of the earliest astronomical observations.