From http://wwp.greenwichmeantime.com/tim...light-time.htm

The "Supermoon", which is the biggest full moon of the year, will be showing off 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.

Saturday's full moon will be ~16 percent brighter than average and will exert about 42 percent more tidal force, making for some great surf waves too!

Check out the science behind all this at http://www.space.com/15540-supermoon...full-moon.html