Solstice

astronomy · seasons · Earth

Two solstices yearly. Every year has two solstices, one around June 20-22 and another around December 20-22. They mark the times when the Sun is at its most extreme positions in the sky.

Most north and south. The June solstice happens when the Sun reaches its farthest north position, while the December solstice happens when it's farthest south. This northerly and southerly movement is what creates our seasons.

Longest and shortest days. On the June solstice in the Northern Hemisphere, daylight lasts its longest, while December brings the shortest day. In the Southern Hemisphere, it's the opposite.

Defines the seasons. Many countries use solstices to officially mark when seasons begin. The June solstice starts summer in the north, while the December solstice starts winter.

Ancient to modern. People have tracked solstices for thousands of years, building monuments like Stonehenge to mark them. Today we still use these special days to understand Earth's tilt and seasons.