This is the first full moon after the December solstice. In North America, we commonly call this full moon the “Old Moon” or “Moon After Yule.” Can you tell me the full moon names? The photograph above is by sky artist Dan Bush, by the way. Be sure to check out his moon page. Look for tonight’s full moon to rise in the east around sunset today (Sunday, January 8). Like every full moon, it’ll climb highest in the sky around midnight and will set in the west tomorrow around sunrise. For general reference, we can say the moon is full all night tonight. Astronomically speaking, though, the moon is full for only an instant. That instant occurs when the moon is most opposite the sun for the month. That happens tomorrow (January 9) at 7:30 Universal Time. For the U.S. time zones, that places the full moon at 2:30 a.m. Eastern Time, 1:30 a.m. Central Time, 12:30 a.m. Mountain Time, and 11:30 p.m. (on January 8) Pacific Time. In North and South America, the moon turns full during the nighttime hours between sunset and sunrise. At this full moon instant, the moon has to be above our horizon, because the sun is shining below it. In other words, at the instant of full moon, the moon shines above the horizon for the nighttime side of the world and below the horizon for the daytime side.
Image credit: Earth and Moon Viewer On the daytime side of the world – like in Africa, most of Asia, Indonesia, Australia and New Zealand – the moon must be below the horizon because the sun is above it. For the Rocky Mountain region in the United States, the moon turns precisely full at midnight, so the full moon shines high overhead while the sun lies underfoot. Watch the January full moon tonight, as it beams from dusk until dawn! Understanding moon phases Understanding the full moon