We usually refer to the second full moon in a month as a Blue Moon or Flower moon. However, that isn’t the case with May’s full moon. Note: not to be confused with Jeff Bezos’ lunar lander of the same name.
Different types of blue moons
However, there is another way for a full moon to earn the ‘blue moon’ label. According to the Old Farmer’s Almanac:
“One season – winter, spring, fall, summer – typically has three full moons. If a season has four full moons, then the third full moon in the season may be called a Blue Moon.”
May only has one full moon, and that falls on Saturday the 18th. But because this weekend’s full moon is the third in this season, it is classified as a blue moon.
This is called a seasonal blue moon. The next time this occurs, will be on 22 August 2021.
When a month has two full moons, it’s referred to as a calendrical blue moon. The next calendrical blue moon – or two full moons in a month – will be in October 2020.
The rarest of all is when a seasonal blue moon and a calendrical blue moon occur in the same year. That will only happen in 2048, with a Blue Moon in January and a seasonal Blue Moon in August.
Then 19 years later, in the year 2067, there will be a Blue Moon on 30 March, and a seasonal Blue Moon on 20 November.
Why is it called a full Flower Moon
All the other full moons have cool names. The full moon in January had the rockstar ‘wolf moon’ moniker, while February’s was called ‘snow moon.’
April and June had cute names too – ‘pink moon’ and ‘strawberry moon’ respectively. In the same way, May’s full moon is referred to as a ‘flower moon’, July will be ‘buck moon’. And so on. Fancy names.
It’s called a Flower Moon because the full moon in May marked a time of increasing fertility. The May full moon as know by a few other names as well: Mother’s Moon, Milk Moon and Corn Planting Moon.
Is a blue moon really blue?
This weekend’s full moon won’t shine with a blueish tint. The moon can appear blue, but it’s very rare and you need unusual sky conditions for the effect to be created. Atmospheric optics expert Les Cowley explains:
“Our eyes have automatic ‘white balances’ just like digital cameras. Go outdoors from a cosy cabin lit by an oil lamp (yellow light) and the moon will appear blue until your eyes adjust.”
The moon can also appear blue after a volcanic eruption or a major forest fire, as both instances will fair the air with ash and dust. Clouds of water droplets, ice crystals or fine-grained sand can have the same effect.
When to view May’s blue moon
On Saturday, 18 May, shortly after 23:00 South African Standard Time. It happens at the same moment for all of us worldwide, yet the time on our clocks vary by time zone. If you’re observing from somewhere else on the planet:
- 21:11 Greenwich Mean Time (London)
- 18:11 Atlantic Time (Puerto Rico and US Virgin Islands)
- 17:11 Eastern Time (New York, Ohio, Carolina, Virginia, etc.)
- 16:11 Central Time (Part of Canada, Mexico, Central America)
- 15:11 Mountain Time (Arizona, Dakota, Texas, Utah, etc.)
- 14:11 Pacific Time (California, Nevada, Oregon, Washington, etc.)
- 13:11 Alaskan Time (US State of Alaska)
- 11:11 Hawaiian Time (Hawaii, Honolulu etc.)
Upcoming lunar events (2019)
If you miss this, these are some of the celestial events you can look forward to in the forthcoming months:
- July 2 – Total Solar Eclipse. A total solar eclipse occurs when the moon completely blocks the Sun, revealing the Sun’s beautiful outer atmosphere known as the corona.
- July 16 – Partial Lunar Eclipse. A partial lunar eclipse occurs when the Moon passes through the Earth’s partial shadow, or penumbra, and only a portion of it passes through the darkest shadow, or umbra.
- August 12, 13 – Perseids Meteor Shower. The Perseids is one of the best meteor showers to observe, producing up to 60 meteors per hour at its peak. It is produced by comet Swift-Tuttle, which was discovered in 1862.
- November 17, 18 – Leonids Meteor Shower. The Leonids is an average shower, producing up to 15 meteors per hour at its peak.
- December 26 – Annular Solar Eclipse. An annular solar eclipse occurs when the Moon is too far away from the Earth to completely cover the Sun.