Myth 64 – Frost is more likely when there is a full moon.

– Posted in: Weather

When someone asks me to name a few of the topics in my book, my usual answer has been, “Oh, things like frost is more likely on a full moon.” There’s always a pause before the questioner says, “You mean that isn’t true?” A look at data, and thinking about the variety of topography in any single area, shows why this myth is made of moonbeams.

In the spring and fall, a frost is more likely to occur on clear nights. But several people have collected data of first and last frosts in their area and then compared it to the phases of the moon. They found no correlation between a full moon and frost. Even without this assessment of the numbers, common sense tells us that this folklore is fiction.

A quick online search of average first and last frost dates shows tremendous variation from one area to another. In Presque Isle, Maine, for example, the average first frost is on the 4th of September, while in Augusta it’s on the 22nd and in Bar Harbor it’s in early October. Other towns and cities in the state list additional days when their first freeze is likely. If frost was more likely on a full moon it stands to reason that those dates would be grouped more closely together.

We also know that the lay of the land has a great deal to do with how cold it gets. Just as the heat from the earth is rising on clear nights, the cold air sinks. So people who live in a valley are more likely to have a frost on such nights than those who live on the hillside. You might have even seen that low gardens in your yard will be frosted while other beds are not.

frosty lawn

A clear night, which makes the full moon visible, is the more likely cause of a frosty lawn in the morning.

Moon myth-busters are fond of saying that it’s likely this belief began because clear, full moon nights make an impression on us. Over the ages, humans have marked the passage of time and the seasons by the phases of the moon and the full moon determines many religious calendars and celebrations. Perhaps as the seasons change, the full moon just seems more important.

full moon over tree line

A full moon speaks to us in our innermost being.

Did You Know…

Many cultures and traditions give a special name to the full moon of each month. Here are some of them:

  • January: “Wolf Moon”
  • February: “Snow Moon”
  • March: “Sap Moon”
  • April: “Seed Moon”
  • May: “Flower Moon”
  • June: “Rose Moon”
  • July: “Hay Moon”
  • August: “Sturgeon Moon”
  • September: “Harvest Moon
  • October: “Hunter’s Moon
  • November: “Frosty Moon”
  • December: “Long Nights Moon”


If gardeners named the full moon, I think they would be something like this:

  • January: “Seed Catalog Moon”
  • February: “Internet Plant Shopping Moon”
  • March: “First Trips to Garden Center Moon”
  • April: “Plant Lust Moon”
  • May: “Dirty Fingernails Moon”
  • June: “Still Have Plants Waiting to go in Garden Moon”
  • July: “Crabgrass Explosion Moon”
  • August: “Ripe Homegrown Tomatoes! Moon”
  • September: “Houseplants Back Indoors Moon
  • October: “Frost Kill Sadness/Relief Moon”
  • November: “Pleased Not to be Weeding Moon”
  • December: “Long Nights Moon”

This is an excerpt from Coffee for Roses: …and 70 Other Misleading Myths About Backyard Gardening by C.L. Fornari, available for purchase on May 16, 2014–two days after the full moon.

About the Author

C.L. Fornari is the author of The Cocktail Hour Garden and Coffee for Roses. She gardens at Poison Ivy Acres on Cape Cod and can be found online at

In its own way, frost may be one of the most beautiful things to happen in your garden all year . . . Don’t miss it. Like all true beauty, it is fleeting. It will grace your garden for but a short while this morning. . . . For this moment, embrace frost as the beautiful gift that it is.

~Philip Harnden in A Gardener’s Guide to Frost: Outwit the Weather and Extend the Spring and Fall Seasons

Comments on this entry are closed.

C.L. Fornari May 22, 2014, 8:15 pm

Thanks, All! The gardeners’ version of the full moon names was fun to write. We have to take every opportunity to laugh about plants and gardening, right?

Jeff Morgan May 21, 2014, 7:50 pm

I never knew that. I like “Hunters Moon” because I love the fall and “Rose Moon”, because who doesn’t love fresh roses?? Great post, as usual.

C.L. Fornari May 15, 2014, 8:25 pm

I do grow Poison Ivy quite well here… do you know about Zanfel for poison ivy? Once you have the rash this product makes it go away in a couple of days. It’s truly worth what it costs – no gardener should be without a tube or two in the bathroom cabinet.

Sally May 15, 2014, 7:42 pm

Poison Ivy Acres….I got a real chuckle out of that! My husband is on the recovering side of a nasty case…..that’s spring in NE for ya! Your list of gardeners moons was great! and so true! Happy Gardening!

Donna@GardensEyeView May 15, 2014, 4:35 pm

Great post…I love moon lore and myths and I love the gardener names for the moon…looks like a great book.

C.L. Fornari May 14, 2014, 7:38 pm

Thanks, all! Writing Coffee for Roses was so enjoyable and my goal was to make the truth about these 71 myths even more entertaining than the myths themselves. This was a book that made me smile as I wrote it, and I’m glad that you enjoyed the gardener’s moon names too.

Landscape Gardener May 14, 2014, 2:27 pm

Hi C.L,
Interesting topic regarding full moons and frost over here in Ireland we do not worry too much about the full moon and frost it more about the full moon and the soft falling rain! Love the gardener full moon titles I will share with friends!

Diana May 14, 2014, 7:42 am

Very interesting. I love the full moon names for gardeners, too. You’re probably right about the full moon standing out in our minds. Can’t wait to get the book and see what other myths you debunk!

gail eichelberger May 14, 2014, 7:30 am

Love the gardener moon names!

Kathy from Cold Climate Gardening May 14, 2014, 7:23 am

Thank you, C.L., for an interesting guest post. I particularly like your full moon names for gardeners!