A solstice is an astronomical event that happens twice each year, when the tilt of the Earth’s axis is most inclined toward or away from the Sun, causing the Sun’s apparent position in the sky to reach its northernmost or southernmost extreme. The name is derived from the Latin sol (sun) and sistere (to stand still), because at the solstices, the Sun stands still in declination; that is, the apparent movement of the Sun’s path north or south comes to a stop before reversing direction. The term solstice can also be used in a broader sense, as the date (day) when this occurs. The solstices, together with the equinoxes, are connected with the seasons. In some cultures they are considered to start or separate the seasons, while in others they fall nearer the middle.
Why summer starts today, and why it’s the longest day of the year—but not the hottest.Related