Unauthorized use is prohibited.įor millennia, cultures around the world have devised ways to celebrate and revere these celestial events-from building structures that align with the solstice to throwing raucous festivals in its honor. Earth is farthest from the sun about two weeks after the June solstice, during the Northern Hemisphere's summer. Earth makes its closest annual approach of the sun about two weeks after the December solstice, during the Northern Hemisphere's winter.

In addition, planets such as Mars have less circular orbits than Earth's, which means that their distances from the sun vary more dramatically than ours do, with correspondingly bigger effects on seasonal temperature.Įarth’s axial tilt plays a much bigger role than its near-circular orbit in governing annual seasons. First, planets vary in their axial tilts: Venus's axis of rotation is tilted by just three degrees, so there's much less seasonal difference between the Venusian summer and winter solstices than those on Earth.

It's worth noting, though, that other planets' seasons don't climatically equal those on Earth for a few reasons. In fact, planetary scientists use solstices and equinoxes to define 'seasons' for other planets in our solar system. Do other planets experience solstices?Įarth is not the only planet with solstices and equinoxes any planet with a tilted rotational axis would see them, too. (That’s as far north as you can go and still see the sun directly overhead.) During the Northern Hemisphere’s winter solstice, the sun appears directly over the Tropic of Capricorn, the Tropic of Cancer’s southern mirror image. When it’s a summer solstice in the Northern Hemisphere, the sun appears directly over the Tropic of Cancer, the latitude line at 23.5 degrees North. You can also think about solstices in terms of where on Earth the sun appears. During the Northern Hemisphere’s summer solstice-which always falls around June 21-the Southern Hemisphere gets its winter solstice. During the Northern Hemisphere's winter solstice-which always falls around December 22-the Southern Hemisphere gets its summer solstice. The hemisphere tilted most toward our home star sees its longest day, while the hemisphere tilted away from the sun sees its longest night. On two moments each year-what are called solstices-Earth's axis is tilted most closely toward the sun. The Southern Hemisphere's seasons are reversed. From September to March, the Northern Hemisphere is tilted away, so it feels like autumn and winter. From March to September, the Northern Hemisphere is tilted more toward the sun, driving its spring and summer. This tilt drives our planet's seasons, as the Northern and Southern Hemispheres get unequal amounts of sunlight over the course of a year. Solstices occur because Earth’s axis of rotation is tilted about 23.4 degrees relative to Earth's orbit around the sun. ( Here's the difference between astronomical and meteorological seasons.) What are solstices? So what exactly are solstices-and how have they been celebrated throughout history? Here’s all you need to know.

However, today’s meteorologists officially use temperature records instead to draw lines between the seasons. Traditionally, summer and winter solstices helped mark the changing of the seasons-along with their counterparts, the spring and autumnal equinoxes. Solstices occur at the same time around the world, but their local times vary with time zones. South of the Equator, this same moment marks the unofficial beginning of winter. This year, the Northern Hemisphere's summer solstice falls on June 21 at 10:57 a.m.

Summer equinox solar radiation