Blue Moon - The Blue Moon of 2012

Our Blue Moon Calculator says that in 2012, there is a Blue Moon in August. You may have heard or read reports which said that the Blue Moon really occurs in September. Who is right?

Well, you can see Blue Moons in either month, but it depends where in the world you live.

Let's start with the basic astronomical facts. The three Full Moons in August and September 2012 are as follows:

2 August	at	03:27 GMT
31 August	at	13:58 GMT
30 September	at	03:18 GMT

These dates and times have been calculated rigorously using the same methods as those employed by the United States Naval Observatory and by Her Majesty's Nautical Almanac Office. They are given in Greenwich Mean Time which is the standard time zone used by astronomers worldwide.

Notice that the second Full Moon in the list occurs early in the afternoon of 31 August. In New Zealand, which is 12 hours ahead of GMT, the difference in time zone changes the month in which the Full Moon falls. In New Zealand, the Full Moon is in the early morning of 1 September.

Here are those three Full Moons again, but with the dates and times adjusted for several major time zones around the world. For each time zone, the two Full Moons which fall in the same calendar month are highlighted.

City	Time zone	Full Moon 1	Full Moon 2	Full Moon 3
Places East of Greenwich
Auckland	GMT + 12 hours	August 2 15:27	September 1 01:58	September 30 15:18
Sydney	GMT + 10 hours	August 2 13:27	August 31 23:58	September 30 13:18
Tokyo	GMT + 9 hours	August 2 12:27	August 31 22:58	September 30 12:18
Moscow¹	GMT + 4 hours	August 2 07:27	August 31 17:58	September 30 07:18
Riyadh	GMT + 3 hours	August 2 06:27	August 31 16:58	September 30 06:18
The Greenwich Meridian
London¹	GMT + 1 hour	August 2 04:27	August 31 14:58	September 30 04:18
Places West of Greenwich
Buenos Aires	GMT - 3 hours	August 2 00:27	August 31 10:58	September 30 00:18
New York¹	GMT - 4 hours	August 1 23:27	August 31 09:58	September 29 23:18
Chicago¹	GMT - 5 hours	August 1 22:27	August 31 08:58	September 29 22:18
Los Angeles¹	GMT - 7 hours	August 1 20:27	August 31 06:58	September 29 20:18
Anchorage, Alaska¹	GMT - 8 hours	August 1 19:27	August 31 05:58	September 29 19:18
Hawaii	GMT - 10 hours	August 1 17:27	August 31 03:58	September 29 17:18
¹ These places observe daylight saving time in August and September.

As you can see, most of the world has a Blue Moon on 31 August, but New Zealand must wait until 30 September for its Blue Moon.

Once in a Blue Moon

The Blue Moon of 2012