When is the next full moon for North America

Question

When is the next full moon for North America

Answer 1

check the calendar.

Mine says 9/15/08

Answer 2

2008 Aug 16 21:18 Sat  

Answer 3

It's the full moon the evening of August 16, 2008.  The precise moment of full moon is 5:18 p.m. Eastern Daylight Time, but we'll see it when the moon comes up later that evening, around 8 p.m. EDT.

I saw some other writers rather hastily saying that the answer to this question is obvious, such as a mere glance at the calendar, but it is not that simple at all.  If you had asked, for instance, when is the next full moon for New Zealand, the answer would not be the 16th (regardless of what the calenday says) but the evening of Sunday August 17th.  The full moon happens at 9:18 a.m. August 17th New Zealand Standard Time, and the closest evening to this is the evening of the 17th.

The instant of full moon, when the moon is diametrically opposite the sun in the sky, takes place at the same moment everywhere in the world (adjusted for time zones, of course).  However, most people go looking for the full moon in the evening.  If the official instant of the full moon occurs in the daytime, and half the world is in daylight at any given moment, you need to calculate when the nearest evening will be.

August 2008 is an easy pick for most of the world.  Suppose instead you had asked about the September full moon.

The September 2008 full moon happens at 9:08 a.m. September 15th, Greenwich Mean Time.  That's 5:08 a.m. Eastern Daylight Time, of course.  So, is the September  full moon in North America on September 15th?  In one way, it is, shortly before dawn that day.  The moon that night rises around 7:30 p.m. the evening before, however.  People in North America looking for the 2008 Harvest Moon will see it the evening of September 14th, even though most calendars say different.  If people in the Eastern Time zone waited until the evening of September 15th, you'd be about fourteen hours too late.

For those further west, even the official date will be September 14th.  In Hawaii, the September full moon officially comes at 11:08 p.m. September 14th, even though most commerially-produced calendars still give the date as September 15.

So your question is indeed a good one, and a bit tricker than many would have you think.

Answer 4

The same as it is for the rest of the world, August 16, at 9:16 PM. North America doesn't get its own separate full moon - we have to share it with everyone else.