During December, the winter cold fastens its grip, and nights are at their longest and darkest, giving this month’s full moon the name “Cold Moon.” December’s full moon is also sometimes referred to as the Moon Before Yule. Yet another term, “Long Night Moon” is doubly appropriate because the midwinter night is indeed long, and because the moon is above the horizon for a long time. The midwinter full moon has a high trajectory across the sky because it is opposite a low sun.