Blue Moon - The Blue Moon of 2015

Our Blue Moon Calculator says that in 2015, there is a Blue Moon in July. Is that true in all parts of the world? After all, previous Blue Moons have fallen on different days in different parts of the world.

Let's start with the basic astronomical facts. The Full Moons in July 2015 are as follows:

2 July	at	02:19 GMT
31 July	at	10:43 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.

Here are those Full Moons again, but with the dates and times adjusted for several major time zones around the world.

City	Time zone	Full Moon 1	Full Moon 2
Places East of Greenwich
Auckland	GMT + 12 hours	July 2 14:19	July 31 22:43
Sydney	GMT + 10 hours	July 2 12:19	July 31 20:43
Tokyo	GMT + 9 hours	July 2 11:19	July 31 19:43
Moscow¹	GMT + 4 hours	July 2 06:19	July 31 14:43
Riyadh	GMT + 3 hours	July 2 05:19	July 31 13:43
The Greenwich Meridian
London¹	GMT + 1 hour	July 2 03:19	July 31 11:43
Places West of Greenwich
Buenos Aires	GMT - 3 hours	July 1 23:19	July 31 07:43
New York¹	GMT - 4 hours	July 1 22:19	July 31 06:43
Chicago¹	GMT - 5 hours	July 1 21:19	July 31 05:43
Los Angeles¹	GMT - 7 hours	July 1 19:19	July 31 03:43
Anchorage, Alaska¹	GMT - 8 hours	July 1 18:19	July 31 02:43
Hawaii	GMT - 10 hours	July 1 16:19	July 31 00:43
¹ These places observe daylight saving time in July.

As you can see, the Blue Moon falls on 31 July, regardless of time zone.

By contrast, the Blue Moon of 2012 fell on 31 August in most parts of the world, but on 30 September in New Zealand.

In 2009, there was a Blue Moon on 31 December in Europe, Africa, the Americas and Asia as far west as Moscow, but in central and east Asia, Australia and New Zealand, the Blue Moon occurred in the following year, on 30 January 2010. In China, Japan, Australia and New Zealand, there was even a second Blue Moon in 2010, on 30 March.

The 2015 Blue Moon is unusual because it falls on the same day across the entire world.

Once in a Blue Moon

The Blue Moon of 2015