There will be a Supermoon December 3 and 4, 2017. A Supermoon is a new or full moon that comes close to Earth in its elliptical orbit; this is called a Lunar Perigee.
The full moon comes on December 3 and lunar perigee takes place on December 4.
The best time to observe the Supermoon is when the moon is near the horizon during either moonrise or moonset:
Sunday Morning, Dec. 3 – Moonset — 6:49am
Sunday Evening, Dec. 3 – Moonrise — 6:19pm
Monday Morning, Dec. 4 – Moonset — 7:59am
Monday Evening, Dec. 4 – Moonrise — 7:02pm
The Universe is under no obligation to make sense to you — Neil deGrasse Tyson