What is the difference between a solstice and an equinox?
Quick Answer: A solstice marks the longest or shortest day of the year when the sun reaches its highest or lowest point in the sky. An equinox happens when day and night are nearly equal in length because the sun is directly above the equator.
A solstice occurs twice a year, around June 21 and December 21. During these days, the sun's path in the sky is at its extreme north or south. This means one hemisphere experiences its longest day while the other has its shortest.
An equinox also happens twice a year, near March 20 and September 23. At this time, the Earth's tilt is such that the sun sits right over the equator. This balances daylight and nighttime almost perfectly around the globe.