Skywatchers take note: The biggest full moon of the year is due to arrive this weekend.

The moon will officially become full Saturday (May 5) at 11:35 p.m. EDT. And because this month’s full moon coincides with the moon’s perigee — its closest approach to Earth — it will also be the year’s biggest.

The moon will swing in 221,802 miles (356,955 kilometers) from our planet, offering skywatchers a spectacular view of an extra-big, extra-bright moon, nicknamed a supermoon.

PHOTOS: 2011 Supermoon: Readers’ Photographs

And not only does the moon’s perigee coincide with full moon this month, but this perigee will be the nearest to Earth of any this year, as the distance of the moon’s close approach varies by about 3 percent, according to meteorologist Joe Rao, SPACE.com’s skywatching columnist. This happens because the moon’s orbit is not perfectly circular.

This month’s full moon is due to be about 16 percent brighter than average. In contrast, later this year on Nov. 28, the full moon will coincide with apogee, the moon’s farthest approach, offering a particularly small and dim full moon.            More