First day of Winter this year is Monday, December 21. The official time of the Winter Solstice (the moment when the Sun is positioned at it's furthest southern position from the Earth's equator) is 11:47 am CST (1747z) Monday morning. During the day of the Winter Solstice, locations on the north side of the equator see their shortest amount of sunlight for the year. Points on the Earth's surface south of the equator see their most minutes of sunlight for the year.

Source: NWS North Platte