Horse Full Moon | Winter Solstice - December 2021. Earth had a Full Moon in the sign of the Horse.on Saturday, December 18 at 8:36 PM. A few days later on Tuesday morning the Sun enters the Ox on December 21st marking the Winter Solstice: the shortest day and longest night in the Northern Hemisphere. The Solstice is celebration of the return to the light. Let there be light! Continue reading →