When is the first day of winter? December solstice 2018 explained.KrakenSailing
Shortening days and falling temperatures are heralding the arrival of winter across the Northern Hemisphere.This year, the northern winter solstice falls on December 21 at 5:23 p.m. ET (22:25 UT). The solstice happens at the same moment around the world, though its local time depends on which of the 24 times zones you call home. And south of the Equator, the December solstice marks the onset of summer.What is the definition of a solstice, and when do they happen? Is the winter solstice always the first day of winter? Find out what causes these bi-annual astronomical events, as well as how they bring about the shortest and longest days of the year.