A Daytime Full Moon?
Ever wonder why Full Moon calendars sometimes list daylight hours? Find out why!
Full Moons are a topic that gets everyone excited around here. Every time we publish a story, video, or social media post about an upcoming full Moon, Farmers’ Almanac fans respond, and our Moon Phase Calendar remains one of the most popular features on our site.
One thing that causes a lot of confusion, though, is the times we give for the full Moon. Sometimes they fall in the middle of the day when the Moon can’t actually be seen. How is that possible?
A Full Moon Definition
The answer lies in the definition of what a full Moon actually is. Most people think the full Moon lasts for a couple of days, because the Moon appears full for two or three nights, on average. Technically, though, the Moon is only considered full for one specific day. Before and after that, the Moon is really either in waxing or waning gibbous stage respectively, no matter how full it appears.
If you want to get even more technical, though, the Moon is really only “full” for a brief instant. The astronomical definition of a full Moon is when the Sun, Earth, and Moon are all in alignment, forming a straight line, with the Moon on the exact opposite side of the Earth from the Sun. From this position, the Sun’s light shines directly onto the portion of the Moon visible to us, creating a full, bright circle of light.
Full For An Instant
The time that this brief instant takes place is the time you see when you look at a Moon phase calendar. Depending on where you live in the world, the Moon may or may not be visible to you at this exact time, but it is visible to someone somewhere. If the full Moon takes place near midnight, it will be visible to you. If it takes place near noon, it will be visible to people living on the opposite side of the globe.
By the time it gets dark in your part of the world, the Moon will still look full, and be considered full for the entire calendar day. Because the Moon is always in motion, revolving around the Earth at a rate of one full circle every 29+ days, it doesn’t stay perfectly aligned for long. In just one week, the Moon will reach its quarter phase and be “half full,” and in two weeks it will disappear completely from view in its “new” phase.
That’s why the time of the full Moon can fall during daylight hours, regardless of whether or not you can actually see the Moon at that time. This type of daytime full Moon is based purely on astronomical calculations.
Another type of daytime Moon occurs when you can see the Moon in broad daylight. This often happens near the quarter phases, and we have written about that phenomenon here.
Jaime McLeod
Jaime McLeod is a longtime journalist who has written for a wide variety of newspapers, magazines, and websites, including MTV.com. She enjoys the outdoors, growing and eating organic food, and is interested in all aspects of natural wellness.
-
Jaime McLeod#molongui-disabled-link
-
Jaime McLeod#molongui-disabled-link
-
Jaime McLeod#molongui-disabled-link
-
Jaime McLeod#molongui-disabled-link
I really enjoyed your full moon article. I am a first time reader and looking forward upcoming new reads. Thank you.
Great information but I see that the comment section has attracted a flat earth conjecture believer. I am going to refute his comment.
Sorry Cryptoctopus, but “da earf isn’t phlat’ and please stop linking to silly non-credible, unqualified anonymous armchair conspiracy crackpot and flat earth nutjob youtube videos made by other non-credible, unqualified anonymous armchair conspiracy crackpot and flat earth nutjobs.
Now, I went ahead and thought about what you said as you requested, but your flatopian world makes absolutely no sense. If the Sun and moon did what you flatopians think it does, the phases of the moon would occur once every 24 hours instead of once a month. Everyone on earth would see a different side of the moon at the same time, and at Sunset the Sun would shrink to a tiny point of light and would never set, and it would be visible 24 hours per day. Now, stop polluting the comment section of this credible website with your silly flatopian fantasy nonsense.
Thank you for the information
I kelt searching for the new moon dates for 2017 nothing would come up
Hi Angela, we have that information in the Calendar pages of the Almanac (at the top of the page for each month), and while not a list, you can find that information on Moon Phases calendar online here: https://www.farmersalmanac.com/calendar/moon-phases
You have missed the point. It has been observed by astronomers at least 5o times in history of the FULL MOON visible in the daylight. That’s the issue.
If the sun is 93 million miles away and the moon 232 000 miles away. How can we both see them in the sky at the same time?
Under those assumptions…it is impossible.
It’s hard to swallow…but the earth is flat.
(Think about longer than a second before dismissing this idea)
This might help come to grasp with reality:
https://www.youtube.com/watch?v=E2jbpaCszTg
Anything about the moon is so interesting. My son took pictures last nite and we will do so again tonite. Thanks for your information.
Great..simply explained. Thx.
Thank you – great information!
Love the infomation you gave on the blue moon
Love this info on the Blue Moon.! Will e watching Friday!
Thank you for making all information on all subjects so readable and interesting!!
Summer lovers moon