"The last full moon of 2017 will appear especially plump and vibrant in the night sky this weekend.
As it reaches fullness, the moon will also be making its closest approach to Earth around the same time, designating it a “supermoon.”
"Because of the moon’s extra-close approach to Earth, it will appear about 14 percent bigger than if it were at its farthest away point in its orbit. It will shine up to 30 percent brighter, not only because it’s close to Earth, but also because Earth will be nearing its closest to the sun in early January.
"'The sunlight reaching and reflecting off the Moon this time of year is about 7 percent more intense' than in the summer, explains NASA.
"The moon officially turns full at 10:47 a.m. Sunday, but it will look full or very close to full to the naked eye Friday, Saturday and Sunday nights.
"December’s full moon is known as the Cold Moon or Frost Moon because of the cold weather at this time of year. It is also sometimes referred to as the Moon Before Yule (Yule is an old northern European winter festival, associated with Christmas)"
Read more: https://www.washingtonpost.com/news/capital-weather-gang/wp/2017/12/01/supermoon-2017-this-weekends-moon-is-the-biggest-of-the-year/?utm_term=.8f6faf8f7597.