What is a Blue Moon? – Origin and definition

In a few words, a Blue Moon happens whenever we have two Full Moons in a single month. We usually have 4 weeks each month and one Moon phase in each one. The Lunar cycle has approximately 28 to 29 days and the calendar we use nowadays is Solar, thus, the Blue Moon happens once in a while.

The expression “once in a Blue Moon” is very common and its meaning is just like the phenomenon: something that is very rare to happen. For us, Pagans, these events are great opportunities to celebrate a very intense Esbat.

So, what is this all about? Is it blue? Why is it so rare?

Blue Moon: Origin and definition

Many attempts to define a calendar are made throughout the ages and this choice is the Blue Moon origin. We have 3 basic calendar systems:

• Lunar Calendar: The Moon cycles are extremely important and the year has 13 months of 28 days in this system. Extra days are added when it is necessary.
• Solar Calendar: The Solar position and the Seasons of the year are considered, leaving the Lunar cycle aside. There are 12 months with 30 days each and, when it is necessary, one extra day is added;
• Lunisolar Calendar: This calendar system consider the Lunar cycle, the Solar position and the Seasons. Extra months are added when it is necessary.

After many adjustments and considerations, the Solar Calendar was chosen and we use it nowadays.

What does it have to do with the Blue Moon?

Accordingly to the Lunar Calendar, we would have 13 months with one Full Moon in each month. With the Solar Calendar, we have 12 months with 30 or 31 days each so one of the Full Moons was “excluded”. Each Moon cycle has around 29,5 days so, in each month of the Solar Calendar we have one Full Moon. The base calculation between the Lunar cycle and the Solar Calendar is different, so once in a while, we have two Full Moons! We name this phenomenon Blue Moon! The Moon is not necessarily blue, but it can rarely get a blue colour (not exactly on these dates) due to volcanic activities or ice crystals in the air.

This idea, however, is modern. The original idea explains that should be 3 Full Moons during each Season. When there are 4, the third Full Moon is the Blue Moon.

Blue Moon: When is the next?

Accordingly to the site Moon Giant, we can schedule our next Blue Moon Esbats. In 2018 we’ll have two Blue Moons! After 2018 we’ll have one in 2020, one in 2023, one in 2026, and one in 2028. Check the dates for the next decade below

• 31st January 2018;
• 31st March 2018;
• 31st October 2020;
• 31st August 2023;
• 31st May 2026;
• 31st December 2028.

For more future dates or to check the previous dates, check the site Moon Giant.

Spells in the Blue Moon

The Blue Moon is a Full Moon, thus all the Blue Moons are Esbat dates! As the Blue Moon is a rare event, it is good to celebrate your Esbat in a more intense way and cast spells related to the Full Moon occasion as those for your achievements, your success, your goals, for love, and for prosperity.

If you need some suggestions, check these simple spells for the Full Moon.

Have a great Esbat!

Blue Moon Calendar

Below you’ll find a Blue Moon Calendar. You can keep it in your Pinterest folders and prepare for all these special Esbats!

Other posts about the Moon

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