File:Happy Winter Solstice! (27423141859).jpg

Happy solstice! Astronomical winter began at 11:28 a.m. ET on December 21, 2017, marking the shortest day of the year in Earth's Northern Hemisphere. NOAA's GOES-East satellite (also known as GOES-16) captured this full disk geocolor image at the beginning of astronomical winter.

The December solstice marks the exact moment each year when the Earth's Northern Hemisphere reaches its greatest possible tilt away from the sun. The sun's direct rays reach their southernmost point with respect to Earth's equator, along the Tropic of Capricorn, at 23.5 degrees south latitude. As a result, we'll see our shortest day and longest night of the year, and the sun will rise and set at its southernmost points along the horizon.

Although the winter solstice brings the shortest daylight period to the Northern Hemisphere, it’s not the day of the latest sunrise or earliest sunset. Most places in the mid-latitudes see their earliest sunset two weeks before the solstice, while the latest sunrise isn't until early January. This misalignment happens because of Earth’s 23.5-degree tilt and our elliptical orbit around the sun.

Learn more about astronomical and meteorological seasons at goo.gl/7WZfDW