Sunday is the summer solstice, marking the start of astronomical summer north of the equator. It’s the opposite in the Southern Hemisphere, where it is the shortest day of the year and winter will start.

Understanding the Solstice

The word “solstice” comes from the Latin words “sol,” for sun, and “stitium,” which can mean “pause” or “stop.” The summer solstice is the end of the sun’s annual march higher in the sky, when it makes its longest, highest arc.

As the Earth travels around the sun, it does so at an angle, making the sun’s warmth and light fall unequally on the northern and southern halves of the planet for most of the year. The solstices mark the times when the Earth is tipped most extremely either toward or away from the sun.

The summer solstice falls between June 20 and 22. This year it’s June 21. The opposite happens at the Northern Hemisphere winter solstice: the Earth’s upper half leans the furthest away from the sun, leading to the shortest day and longest night of the year.

Original reporting: NBC10 Boston — read the source article.