BUFFALO, N.Y. — People like to use the phrase “once in a blue moon” to refer to the unusual. What an odd coincidence then that 2020, a most unusual year itself, will play host to the not-so-common celestial event.
On Saturday night, a full moon will rise in the east. This will be the second full moon in October, making this one a “Blue Moon.” But there is another, older definition of a blue moon that has to do with seasons rather than months. In that case, the blue moon is the third of four full moons between an equinox and a solstice or vice versa.
The first kind of blue moon mentioned is what we’ll see this weekend. It is known as a “calendrical” blue moon. It will be the first such since March of 2018. After this weekend, we won’t see another one until August of 2023.
It’s easy to see why a calendrical blue moon is uncommon just by looking at some simple math. Each of the 12 months in the modern calendar range between 28 days and 31 days but a lunar cycle, the time from new moon to new moon, is 29.5 days. That means we’d never see a blue moon in February, even in a leap year. Most blue moon months have 31 days. It’s not a requirement, but that extra day compared to 30-day months makes the odds a little bit better.
Now the real question: will the skies actually be clear enough Saturday night to catch a glimpse of the blue moon? As of Wednesday afternoon, the forecast looks promising with scattered clouds and seasonably cool temperatures. The moon will rise above the horizon just before 6:30 p.m.
New episodes of Heather’s Weather Whys are posted to the WGRZ YouTube channel every Wednesday evening. If you have a weather question for Heather to answer, send it to her at heather.waldman@wgrz.com or connect with her on Facebook or Twitter.
