Today is the longest day of the year - summer solstice

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

During the Northern Hemisphere’s summer solstice, the upper half of the earth is tilted toward the sun, creating the longest day and shortest night of the year. This solstice always falls between June 20 and 22.

The solstice is the end of the sun’s annual march higher in the sky, when it makes its longest, highest arc. It then starts retreating and days will get a little shorter every day until late December.

As is retreats southward, the sun will cross over the earth's equator in late September, an event called the autumnal equinox.

During the equinox, both hemispheres get an equal amount of sunlight. On the equator, the sun will be directly overhead at noon. 

Equinoxes are the only time when both the north and south poles are lit by sunshine at the same time.



(AP Photo Esteban Felix)