Tonight – July 19, 2016 – you’ll see a full moon. In North America, we often call the July full moon the Buck Moon, Thunder Moon or Hay Moon. At this time of year, buck deer begin to grow velvety antlers, while farmers are struggling to put hay in their barns amid the sumer season’s frequent thunder showers.
The moon is said to be astronomically full when it’s precisely 180o opposite the sun in ecliptic longitude. This happens at 22:57 Universal Time. At U.S. latitudes, that translates to 6:57 p.m. EDT, 5:57 p.m. CDT, 4:57 p.m. MDT and 3:57 p.m. PDT.
Strictly speaking, we in North America won’t see the moon at the instant that it turns full. For us, the moon will still be below the horizon as the moon turns exactly full. By the time the moon rises over the eastern horizon, we in North America will be looking at a moon that’s slightly past full phase. It’ll be a full-looking waning gibbous moon.
No matter. From almost everywhere worldwide, the moon will appear plenty full to the eye on the night of July 19-20. That’s because at the vicinity of full moon, the moon remains pretty much opposite the sun in Earth’s sky all hours of the night.
Look for the moon to rise in your eastern sky at dusk or early evening, to climb up highest up for the night around midnight and to sit low in your western sky at dawn July 20.
The full moon lies almost opposite the sun, so the path of the July full moon across the nighttime sky will resemble that of the January sun across the daytime sky. Therefore, far-northern regions of the globe won’t see the moon at all tonight. That’s because the July full moon, like the January sun, resides too far south on the sky’s dome to be seen from northern Arctic latitudes.
Bottom line: Look for the full moon on July 19, 2016, lighting up our skies from dusk or early evening until dawn.