PHOENIX - The official start of the winter solstice occurred Saturday morning, at 10:11 a.m. to be exact. But how is the official start of winter even determined?
The winter solstice happens when the sun "reaches its southern most latitude of the year," according to the National Weather Service .
Officials are able to determine precisely when the sun rises to 23 1/2 degrees latitude, south of the Equator, said the NWS. That puts it directly over the Tropic of Capricorn in the Southern Hemisphere.
In simpler terms, this means the sun ends its 6-month journey south and begins its journey north, according to the NWS.