Understanding the Blue Moon
by Cayelin K Castell
In a recent 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 2009 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 2009 to the December Solstice in 2010 we find there are 13 Full Moons. This is not always the case! For example, in 2007 we had 13 Full Moons in the calendar year but only 12 Full Moons from December Solstice 2006 to December Solstice 2007. (See Table below)
In more recent times however the term Blue Moon has also been used to describe the occurrence of two Full Moons in a calendar month. 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 fact, both of these 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. 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 and it doesn’t necessarily happen each time the Full Moon is in zero degrees of the 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.
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 factor that is common to all of them is that these are rare occurrences 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 in your personal or collective experience. For example, I found that the December 2002 Full Moon - Blue Moon was beyond the beyond kind of experience for me and for the entire group I was with at the time. The July 2004 two Full Moons in a calendar month Blue Moon was also especially significant for me, 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 second Full Moon or a Blue 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 then next.
During 2005 and 2006 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 Mont
| 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 2009 to 2010 and 2012 to 2013
| 01. | 2009 | Dec 31 Cancer |
2012 | Dec 28 Cancer |
|
|---|---|---|---|---|---|
| 02. | 2010 | Jan 30 Leo |
2013 | Jan 27 Leo |
|
| 03. | 2010 |
Feb 28 |
2013 | Feb 25 Virgo |
|
| 04. | 2010 | Mar 30 Libra |
2013 | Mar 27 Libra |
|
| 05. | 2010 | Apr 28 Scorpio |
2013 | Apr 25 Scorpio Eclipse |
|
| 06. | 2005 | May 27 Sagittarius |
2013 | May 25 Sagittarius Eclipse |
|
| 07. | 2010 | Jun 26 Capricorn Eclipse |
2013 | Jun 23 Capricorn |
|
| 08. | 2010 | Jul 26 Aquarius |
2013 | Jul 22 Aquarius |
|
| 09. | 2010 | Aug 24 Pisces |
2013 | Aug 16 Aquarius |
|
| 10. | 2010 | Sep 23 Aries |
2013 | Sep 19 Pisces |
|
| 11. | 2010 | Oct 23 Aries |
2013 | Oct 18 Aries Eclipse |
|
| 12. | 2010 | Nov 21 Taurus |
2013 | Nov 17 Taurus |
|
| 13. | 2010 | Dec 15 Gemini Eclipse |
2013 | Dec 17 Gemini |
Two Consecutive Full Moons In The Same Sign
(No Taurus, Gemini, Leo, Cancer)
| 2000 | Feb 19 | 00 Virgo 51 | 2000 | Mar 20 | 29 Virgo 53 |
| 2002 | Jul 24 | 00 Aquarius 18 | 2002 | Aug 22 | 29 Aquarius 39 |
| 2005 | Jun 22 | 00 Capricorn 51 | 2005 | Jul 21 | 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 | Jul 21 | 29 Capricorn 09 |
| 2029 | Aug 24 | 01 Pisces 12 | 2029 | Sep 22 | 29 Pisces 57 |
| 2032 | Jul 22 | 00 Aquarius 30 | 2032 | Aug 21 | 28 Aquarius 34 |
| 2035 | May 22 | 00 Sagittarius 57 | 2035 | Jun 20 | 29 Sagittarius 20 |
| 2038 | Mar 21 | 00 Libra 33 | 2038 | Apr 19 | 29 Libra 29 |
| 2040 | Jul 24 | 00 Aquarius 48 | 2040 | Aug 22 | 29 Aquarius 53 |
April 21st, 2009 at 8:01 pm
There are two New Moons in Cancer in 2009. Cancer is ruled by the Moon, so it is a significant event. Although your article focuses on Full Moons, the opposite is true as well - there will be two New Moons in the same month or sign in between when there are two Full Moons in the same month or sign. These events are just as important, if not more than Full Moons.
During Full Moons, we have both classical planets, the Sun and the Moon, pulling on the Earth in opposite directions. However, during a New Moon phase those gravitational pulls are even greater when you have both the Moon and the Sun tugging on the Earth in the same direction.
Just something to add to your article… <>
Wayne
May 30th, 2009 at 5:42 pm
Thank you Wayne it is true this works for all the Moon phases New Moon, Full Moon and the First and Last Quarter Moons as well. Plus as you mentioned when the Moon is Perigee (or closest to the Earth) the New Moon and Full Moon will have a greater affect on the tides and the weather patterns as was evidenced last summer (2008) when we had several occurrences of these Moon phases near the perigee. I was in Wisconsin when they had all that mid-west flooding and tornadoes just after a Full Moon near Perigee that was also an out-of bounds Moon crossing Galactic Center. So that adds a whole other dimension to consider as well. This year we will have an out-of bounds New Moon near the June Solstice. and the Moon will be at perigee 15 hours after the New Moon creating the possibility of HIGH tides and unusual weather patterns.