When Is July's Full Moon, the Biggest and Brightest Supermoon of the Year?

Later this week, the July full moon will grace the skies in what promises to be a treat for sky-watchers.

The full Buck Moon, which will rise on Wednesday, will be a supermoon, the biggest and brightest of the year, making this event extra special. It's called a Buck Moon because the antlers of male deer (bucks) are in full-growth mode at this time.

Full moons are a lunar phase that occurs roughly once every month when the moon is located opposite the sun in space, with the Earth in between.

Technically, the moon turns completely full only for a moment, which this month will occur on Wednesday. However, the moon will appear fully illuminated to most observers for around three days centered on this time, appearing like a perfect circle in the night sky.

According to the Old Farmer's Almanac, the moon will turn full at 2:38 p.m. ET on Wednesday (11:38 a.m. PT).

For observers in North America, the moon will be below the horizon at the moment of peak illumination, so you will need to wait until after sunset to see it. Look toward the southeast shortly after sunset to catch a glimpse of the moon rising.

A full moon
Supermoons, like the one that will be visible Wednesday night, are larger and brighter than regular full moons. Above, a full moon. iStock

All full moons rise at sunset and set at dawn when the sun rises again. This is because full moons are located exactly opposite the sun in the sky, as seen from Earth. As a result, the face of the moon that we can see is fully illuminated by the sun's rays at these points.

July's full moon can also be considered a supermoon. This is a nonscientific term popularly used to describe a full moon that is approaching its perigee—the point in our natural satellite's orbit when it is closest to Earth.

The moon's orbit around the Earth is actually elliptical, or oval-shaped, rather than perfectly circular, meaning the distance between the two bodies varies over time.

There is no strict definition of a supermoon, but it is most often used to describe any full moon that occurs when the moon is within 90 percent of its minimum distance from the Earth.

In the case of Wednesday's supermoon, it will be closer to Earth than any other full moon this year (about 222,089 miles away). This makes it the biggest and brightest supermoon of the year.

But while supermoons are technically larger and brighter than regular full moons, the difference can often be difficult to spot for most observers.

"A supermoon is about 7 percent larger and 15 percent brighter than the average full moon, but casual stargazers will not recognize this at first glance. Those are not really obvious variations," astronomer Gianluca Masi of the Virtual Telescope Project told Newsweek.

"But the difference in apparent size can be seen on photographs. Take a picture of the upcoming supermoon and compare it with another picture of a typical full moon, provided you use the very same equipment/zoom factor. You will see the difference," he said.