The date at which the sun’s zenith is at its furthest point from the equator. (The word solstice derives from the Latin solstitium, meaning “sun-stopping”, referring to the date on which the point on the horizon at which the sun rises and sets appears to stop and reverse direction). There are two solstice dates per year. In the northern hemisphere, the one in June is designated the summer solstice (which marks the transition from spring to summer and is the time at which the sun reaches its northernmost point), and the one in December is designated the winter solstice (which marks the transition from fall to winter and is the time at which the sun reaches its southernmost point).
