Winter solstice 2019 in the Northern Hemisphere will be today (Sat) 
at 8:19 P.M. (Pacific Time).

The winter solstice, also known as midwinter, occurs when one of the Earth’s
poles has its maximum tilt away from the Sun. It happens twice yearly, once
in each hemisphere (Northern and Southern). For that hemisphere, the winter solstice is the day with the shortest period of daylight and longest night of
the year, when the Sun is at its lowest daily maximum elevation in the sky.

At the pole, there is continuous darkness or twilight around the winter
solstice. Its opposite is the summer solstice.   

Illumination of Earth by the Sun on the day of the December solstice.