This year a full moon will occur on the winter solstice (commonly called
the first day of winter), Dec. 22nd.  This is the first time this has
happened in 133 years.

Since a full moon on the winter solstice occurs in conjunction with a lunar
perigee (point in the moon's orbit that is closest to Earth), the moon will
appear about 14% larger than it does at apogee (the point in its elliptical
orbit that is farthest from the Earth).

Since the Earth is also several million miles closer to the sun at this
time of the year than in the summer, sunlight striking the moon is about 7%
stronger, making it brighter.

Also, this will be the closest perigee of the Moon of the year since the
moon's orbit is constantly deforming.  If the weather is clear and there is
a snow cover where you live, it is believed that the moonlight will be so
bright that even car headlights will be unnecessary.

On December 21st 1866, the Lakota Sioux took advantage of this combination
of occurrences and staged a devastating retaliatory ambush on soldiers in
the Wyoming Territory.

Our ancestors 133 years ago saw this.  Our descendants 100 or so years from
now will see it again.
Look for it on the 22nd.