Understanding The Blue Moon
(with dates to 2040)

by Cayelin K Castell

The picture to the right is a Blue Moon photographed in October 2003 by Tom King of Watauga, Texas.

What is a Blue Moon???

Popular understanding says a Blue Moon is when two Full Moons land in the same calendar month. The next Blue Moon by this definition is May 2 and May 31 2007. Apparently our current understanding of a Blue Moon comes from a 1940’s article that appeared in astronomy magazine suggesting the definition of a Blue Moon was the second Full Moon in a calendar month. This event only happens every two and a half to three years.

In a Sky and Telescope article we learn the original definition of a Blue Moon is referring to 4 Full Moons in one season. In this instance a season is defined as the time between a Solstice and Equinox or an Equinox and Solstice. (See Table below) There are four seasons in a year and generally three Full Moons in each season or 12 Full Moons per year. Occasionally we find there are 4 Full Moons in one season and 13 Full Moons in a year marking the annual solar and lunar cycle from December Solstice to Solstice.

If we look at the year 2005 we only have 12 Full Moons in that calendar year from Jan 1 to Dec 31. However, if we consider the number of Full Moons from the December Solstice in 2004 to the December Solstice in 2005 we find there are 13 Full Moons. This is not always the case! For example, in 2004 we had 13 Full Moons in the calendar year but only 12 Full Moons from December Solstice 2003 to December Solstice 2004 and December Solstice 2002 to 2003. We have to go back to Dec 20, 2001 to Dec 19, 2002 and Dec 22, 1999 to Dec 11 2000 to find 13 Full Moons between the December Solstices. (See Table below)

In fact, both of these types of Blue Moon's occur with about the same frequency. However, four Full Moons in a season has greater astronomical significance than two Full Moons in a calendar month. This is because our calendar months are not astronomically based on the yearly seasonal cycle or the monthly lunar cycle.

There is a third definition of a Blue Moon suggesting the term Blue Moon may have originated from the bluish tinge the Moon gets when viewed through smoke. In this case, the theory is that someone saw the Moon appearing quite blue through the smoke of a large distant fire (like a forest fire) and therefore the term Blue Moon was literal.

A fourth occurrence that happens with about the same frequency as the first two examples is when we have two Full Moons in a row in the same sign. These Full Moons do not occur in the same calendar month becuase this only occurs when the first Full Moon is in Zero or One degree of the sign and the next Full Moon is in 28 or 29 degrees of the same sign. For example July 24, 2002 we had a Full Moon at 1 degree and 18 minutes of Aquarius, the following month on Aug 22 we had another Full Moon at 29 degrees and 39 minutes of Aquarius. This also happened in 2005 on June 22 when the Full Moon was at Zero Degrees and 51 minutes of Capricorn and then on July 21 it was at 28 degrees and 47 minutes of Capricorn. (See table below).

In all these definitions of a Blue Moon, either as seen through smoke, or the number of Full Moons in a season, or two Full Moons in a month, or two Full Moons in the same sign, the common factor is how rare these occurrences are captivating our imagination. It is important to remember that each Full Moon has its own unique magic and mystery associated with it and is an opportunity to experience greater illumination of our essential divine nature regardless of whether it is a so-called Blue Moon or not.

Below are some Blue Moon dates to ponder. Do you notice a pattern? For the dates that have already passed it might be helpful to note if any of these Timings were especially significant for you personally. For example, the December 2002 Full Moon - Blue Moon was beyond the beyond powefully activating for the group I was with at the time. The July 2004 two Full Moons in a calendar month Blue Moon ceremony catalyzed a revelation that changed my life. However, that was also a time that coincided with a powerful Pluto transit to my natal Moon so it was more than likely that particular Full Moon was a further catalyst for the process already underway and less likely that it was the fact that it was the second Full Moon that month.

It helps to know that experientially the Moon rises appearing full for three nights, the day before, the day of and the day after the exact Full Moon indicating the potency of the Full Moon Window lasts for three days. Traditionally the Full Moon is the phase of fruition or fulfillment.

The Moon is often associated with the number 13. However the Moon actually connects with the numbers 12, 13 and 19. If you are tracking the Moon return to a certain zodiacal degree, say zero Capricorn, it will return to that degree every 27.3 days and if you divide 27.3 into 365 the closest whole number is 13. If you are tracking the Moon phases from Full Moon to Full Moon or any other phase it returns every 29.5 days. When we divide 29.5 into 365 the closest whole number is 12. So it is only every few years we will actually have 13 Full Moons in either a calendar year or a seasonal year from one December Solstice to the next.

Lunar Standstill 19 year Cycle
During 2005 to 2007 when the Moon is full near zero degrees Capricorn or zero degrees Cancer it is rising near at its maximum extreme 5 degrees beyond the bounds of where the Sun always rises at the Solstices. This can only happen every 19 years. Every 19 years the Sun and Moon will return to the same sign and degree they were 19 years earlier on any given date. So we are in a rare time that can only happen every 13,000 years when the Moon is going through its Lunar Extreme and rising on the galactic plane. It would have been nearly 26,000 years ago Earth experienced the Lunar Standstill in the configuration happening now. So in that sense we are experiencing the rarest possible Blue Moon Phenomenon in 2006 when the Moon rise near zero Capricorn or Cancer is aligned with the galactic plane. This is truly worthy of our consideration when remember that our conscious participation with these events helps to inform the unfolding mysteries as much as they are informing us.

Blue Moon Dates Based on 4 Full Moons in a Season
Jun 2000 Fourth Full Moon in a Season (Mar 20, Apr 18, May 18, Jun 17)
Dec 2002 Fourth Full Moon in a Season (Sep 21, Oct 21, Nov 20, Dec 19)
Sep 2005 Fourth Full Moon in a Season (Jun 22, Jul 21, Aug 19, Sep 18)
Jun 2008 Fourth Full Moon in a Season (Mar 21, Apr 20, May 19, Jun 18)
Dec 2010 Fourth Full Moon in a Season (Sep 23, Oct 23, Nov 21, Dec 21)
Sep 2013 Fourth Full Moon in a Season (Jun 23, Jul 22, Aug 19, Sep 19)
Jun 2016 Fourth Full Moon in a Season (Mar 23, Apr 22, May 21, Jun 20)
Jun 2019 Fourth Full Moon in a Season (Mar 21, Apr 19, May 18, Jun 17)
Jun 2024 Fourth Full Moon in a Season (Jun 22, Jul 21, Aug 19, Sep 18)
Jun 2027 Fourth Full Moon in a Season (Mar 22, Apr 20, May 19, Jun 18)
Dec 2029 Fourth Full Moon in a Season (Sep 22, Oct 22, Nov 21, Dec 20)
Jun 2036 Fourth Full Moon in a Season (Mar 23, Apr 22, May 22, Jun 20)
Jun 2038 Fourth Full Moon in a Season (Mar 21, Apr 29, May 18, Jun 17 +eclipse) Sep 2040 Fourth Full Moon in a Season (Jun 26 + eclipse, Jul 24, Aug 22, Sep 20)

Full Moon Dates Based on Two Full Moons in a Calendar Month
Nov 2001 Two Full Moons November 1 and 30
Jul 2004 Two Full Moons July 2 and 31
May 2007 Two Full Moons May 2 and 31
Dec 2009 Two Full Moons December 2 and 31
Aug 2012 Two Full Moons Aug 2 and 31
Jul 2015 Two Full Moons July 2 and 31
Jan 2018 Two Full Moons January 2 and 31 with no Full Moon in February
Oct 2020 Two Full Moons October 1 and 31

Full Moons in Solar Year (Dec Solstice To Dec Solstice) for Calendar Year 2004 to 2005

1. 2004 Dec 26
2. 2005 Jan 25
3. 2005 Feb 23
4. 2005 Mar 25
5. 2005 Apr 24
6. 2005 May 23
7. 2005 Jun 21
8. 2005 Jul 21
9. 2005 Aug 19
10. 2005 Sep 17
11. 2005 Oct 17
12. 2005 Nov 15
13. Dec 15 2005

Two Consecutive Full Moons In The Same Sign
(No Taurus, Gemini, Leo, Cancer)

2000 Feb 19      00 Virgo 51                2000 Mar20        29 Virgo 53
2002 Jul 24        00 Aquarius 18         2002 Aug22      29 Aquarius 39
2005 Jun 22       00 Capricorn 51        2005  Jul21      28 Capricorn 47
2008 Apr 20        00 Scorpio 43           2008 May 20    29 Scorpio 27
2010 Sep 23      00 Aries 15                2010 Oct 23      29 Aries 33
2013 Jul 22        00 Aquarius 06         2013 Aug 21      28 Aquarius 11
2016 May 21     01 Sagittarius 14      2016 Jun 20      29 Sagittarius 33
2019 Mar 21     00 Libra 29                 2019 Apr 19      29 Libra 27
2021 Jul 24       01 Aquarius 26          2021 Aug 22      29 Aquarius 37
2024 Jun 21      01 Capricorn 07        2024 Jul21       29 Capricorn 09
2029 Aug 24      01 Pisces 12             2029 Sep 22     29 Pisces 57
2032 Jul 22       00 Aquarius 30          2032 Aug21      28 Aquarius 34
2035 May 22      00 Sagittarius 57      2035 Jun 20      29 Sagittarius 20
2038 Mar 21      00 Libra 33                 2038  Apr19     29 Libra 29
2040 Jul 24       00 Aquarius 48          2040  Aug22     29 Aquarius 53