Full Moon – Friday the 13thJune 13th, 2014 at 4:20 am by Bill Steffen under Bill's Blog, News, Weather
I hope this doesn’t get too confusing…but, here goes….We have both a full moon and today is Friday the 13th. Well, we do, but Milwaukee doesn’t. That’s because the exact time of the full moon was 12:11 am EDT. So…the full moon plus Friday the 13th thing works for the Eastern Time Zone (and Asia, Europe, S. America and Africa), but not for the Central, Mountain and Western Time Zones in the U.S., where the full moon came the evening of 6/12. Since there are 7 days in a week, there is a 1 in 7 chance that the 13th of the month will come on a Friday (or 14.29%). A given year can have anywhere from 1 to 3 Friday the 13ths. There’s a full moon on the 13th of the month about every 3 years. The time between full moons is 29 days, 12 hours and 44 minutes. So, we can get 2 full moons in a given month (the 2nd full moon in a calendar month is called a “blue moon”), and on rare occasion, February can have no full moon at all. That last happened in 1999 and will happen next in 2018. On average, there are 12.37 full moons in a year and 365.2422 days in a year (and that’s a whole new set of fun math problems…because that’s an odd number, we add a leap day every 4th year…that would work if it was exactly 365.25 days in a year…but because of that .2422, we skip leap year if we can divide 100 into the year…so we didn’t have leap year in 1800 or 1900 – but…we DO have leap year if you can divide 400 into the year, so we DID have leap year in 2000). Now, there are 12 days a year that are the 13th. That would be 3.29% of the days of the year. The odds of any one day being a full moon are 3.39 percent. So you multiply those numbers and…The odds of any single day being a Friday, the 13th and a full moon are about .0159%. Since there are 365.25 days in a year, you multiply those two numbers and you get a 5.81% chance that any year will have a single day that is a Friday the 13th and have a full moon – or about once every 20 years. The last Friday the 13th with a full moon was Oct. 13th, 2000 and the next Friday the 13th with a full moon will be Aug. 13, 2049. The last June 13th with a full moon was in 1919 (my almost 95-year old mother missed that one by less than a month). The next full moon on Friday, June 13th will be in the year 2098. This is the full moon closest to the Summer Solstice (June 21 this year), so it’s the full moon that is lowest in the sky, rising in the SE and setting in the SW. The June full moon is sometimes called the “Honey Moon” because being lower in the sky and coming during the often hazy summer season, it often has a yellowish or honey hue. The full moon of June is also called the Strawberry Moon. The picture is the June “Honey Moon” over the Washington Monument (From Bill Ingalls and NASA). Many couples get married in June – and the term “honeymoon” goes back to the 1500s. It’s been fun to write this article…all the while one of my two cats has been chasing a fly – I’ve been enjoying her leaps and bounds – her compensating for her inability to fly. I’ve seen her leap and swat down flies in mid-air (and eat them…she won’t eat mice, just plays with them…but insects, that’s kitty chow). She has wonderful vision (and I think other senses as well) compared to me. So far, the fly has stayed a step ahead of her.