Is it going to be a harsh winter? Or will it be mild? How can you tell?

Do you rely on the almanac? Or do you turn to woolly worms?

For many, many years, legend has held that woolly worms can predict whether the coming winter will be mild or harsh. Is there any truth to this belief? Or is it an old wives’ tale?

Woolly worms are actually the larval stage of the Isabella tiger moth (Pyrrharctia Isabella). They are known by various names, including “woolly bear caterpillars,” “banded woolly bears,” “fuzzy bears” and “black-ended bears.”

Woolly worms get their name from their fuzzy appearance. They have black bands at each end with a red-brown band in the middle.

Each autumn, woolly bear caterpillars take shelter under leaves and other low-lying vegetation. In the spring, they complete their transformation into Isabella tiger moths.

People who believe woolly worms can predict the weather think that a narrow red-brown band means a harsh winter. The wider the red-brown band is, the milder the coming winter is supposed to be.

There are several towns in the United States that hold annual woolly worm festivals each fall. In addition to caterpillar races, these festivals also usually feature an official declaration of the woolly worm’s prediction for the coming winter.

But how accurate are woolly worms at predicting the weather? As it turns out, they’re not so accurate.

Scientists who have tested woolly worms’ predictions have found that there is no correlation between woolly worms’ bands and winter weather. Instead, they note that the color and size of a woolly worm’s bands are likely affected by several factors, including availability of food, conditions during development, age and species.

Woolly worms aren’t the only creatures that people look to for information about the weather, though. Here are some of the other animals and insects that people believe have weather-predicting abilities:

  • Groundhogs: Each February 2, Americans wait for groundhog Punxsutawney Phil to predict whether we will have six more weeks of winter or an early spring. Unfortunately, the National Climatic Data Center claims that Phil has only correctly predicted the weather about 39 percent of the time.
  • Frogs: Some people believe that frogs croak louder and longer than normal when bad weather is on the way.
  • Birds: How high are the birds in the sky? This is the question some people ask themselves. They believe that high-flying birds signal clear weather, and low-flying birds mean a storm is headed your way.
  • Bees: If you notice that the bees buzzing around your flowers have suddenly gone missing, you can bet that bad weather may be on the way.
  • Ladybugs: As the old saying goes, “When the ladybugs swarm, expect a day that’s warm.” On the other hand, if they’re looking for shelter, cold weather is on its way.
  • Ants: If you notice ants building up their mounds for extra protection or even covering the mounds’ holes, you might want to prepare for some rain!

Can all of these animals and insects successfully predict the weather? Not always!

However, scientists do believe that many animals and insects have heightened senses that allow them to predict when certain types of weather are imminent. Confirm with the weatherman, but pay attention when you see animals and insects behaving in strange ways!


78 Join the Discussion

1 Star2 Stars3 Stars4 Stars5 Stars  (36 votes, avg. 4.36 out of 5)
  1. Yay, first comment. Do you guys know the poptropica website? It is a cool website just like Wonderoplis, but you guys are cooler because we can talk to you though comments. Anyway, awesome wonder of the day.

    P.S. I am 8 yrs old.

    • Hi, Nour! We have never heard of that website, but THANK YOU for letting us know that you think Wonderopolis is cool because we can chat back and forth though comments! We’re glad you’re our Wonder Friend! :-)

  2. We thought the video was very strange and short! We want more worm!
    They can’t predict as well as we thought, and the video was awkward – the worm was just doing the WORM! :)

    • What a great comment, 5A in Gibbons! That worm was really moving, wasn’t it? We think if we had a huge video camera staring down on us, we’d try to to “the WORM” to get out of there as fast as we could, too! Thank you so much for visiting Wonderopolis today and for letting us know what you thought about the video for today’s Wonder! :-)

  3. We think it is cool how animals can predict the weather. Here is what we don’t understand: why is it that people still believe that woolly worms can predict the weather, if the worms are rarely accurate?
    P.S. We love learning all the Wonder words and each interesting wonder on Fridays when we meet!:-)

    • Hi, 4th Gr. LEAPers! We’re so happy to hear from you today! You ask a GREAT question! We’re not sure why some people still believe that woolly worms can predict the weather even though scientists have proven that they probably can’t. Maybe people have a hard time letting go of things they thought were true for their whole lives. Maybe they don’t believe the scientists. Or, maybe they haven’t heard the results of the scientists’ woolly worm weather experiments yet. We think they should visit Wonderopolis, just like you did, so they can learn more about woolly worms! :-)

    • Hello, Lilly and Britney! Thanks for leaving us this comment! You can find LOTS of great facts about woolly worms in today’s Wonder of the Day®! Do you have woolly worms where you live? Have you ever seen a woolly worm up close? We’d like to know what you think about woolly worms! :-)

  4. Dear Wonderopolis,

    I really enjoyed this Wonder! :) I learned that sometimes animals are relied on to predict the weather, but aren’t right most of the time! I liked that animals are good for more than just admiration. But, some animals aren’t wanted around. This lead me to wonder.. Is there any ways you yourself could predict the weather? Like for in your area? I also wonder if persimmons will predict the weather.

    –Hannah from Team Turner
    :) 😉 :) :)

  5. Dear Wonderopolis,
    Today I learned about woolly worms and how some people think that they can actually tell the weather. I like the part when it tells you about the stripes on their backs. I wonder if when a woolly worm predicted the weather if it EVER came true. I think tomorrow’s wonder will be about butterflies.

    • Thank you so much for visiting today’s Wonder of the Day® about woolly worms and also for trying to guess what tomorrow’s Wonder might be, Kellan! We really enjoyed reading your comment! :-)

    • Well, we’re glad today’s Wonder was all about them then, Arielle! Thank you for sharing your comment with us today to let us know how much you like woolly worms! :-)

    • We’re so happy to hear that you’re such a super fan of Wonderopolis, andrewanna! We like learning stuff, too, and we’re glad you visited us today! :-)

    • Thank you for sharing your comment with us today, David! We’re glad you learned some cool new facts about woolly worms! :-)

    • Your question about snow leopards would make a WONDERful Wonder of the Day®, Madison! Thank you so much for suggesting it! :-)

    I loved today’s WONDER! I love woolly worms. I think tomorrow’s WONDER will be about flies, because most flies live for just a couple days. You should do a WONDER about why camels have humps on their backs.
    Jo Jo
    :) 😉 😀

    • Thanks for letting us know you liked this woolly worm Wonder, Jo Jo! We think a Wonder of the Day® about camels and their humps is a fantastic idea! Thank you so much for suggesting it! :-)

    • We figured it out, Jo Jo! Your real name is Saydi! We’re glad you told us your real name, but it’s OK if you want to keep using “Jo Jo,” too! Thank you for being such a GREAT Wonder Friend with any name you use! :-)

    • Hello, Kaylee and Keeley! Thanks so much for visiting this Wonder of the Day® and for sharing what you think about woolly worms predicting the weather! :-)

    • Hi there, Faith! Thank you for leaving us a comment to let us know you stopped by this Wonder of the Day® about woolly worms! :-)

    • We’re super happy to hear that the video for this Wonder made you “LOL,” Faith! It made us “LOL,” too! We liked watching how fast that worm could wiggle through the grass! :-)

  7. I knew they couldn’t!
    I mean, come on, really? Even most of the meteorologists can’t even predict what the weather’s going to be.
    See you tommorow!
    mak – makayla

    • We like reading your comments each day, Mak! We like the way you WONDER even more about each day’s Wonder after you’ve explored it! Thanks for being a great Wonder Friend! :-)

  8. Wonderopolis is awesome. We think you should do one on puppies and horses or hippos. We love woolly worms. They rock! Ya, go, woolly worms, YA!!!!!!!!!!!! :)

    • Hi, Kimberlee! We’re glad you shared your opinion of the video for this Wonder of the Day®! We thought it would be fun to see a woolly worm up close! We thought he moved really fast for a worm, didn’t you? :-)

  9. I am confused, because I heard that when a woolly worm gets really long, the summer would get longer. Please tell me if I am right. Talk to you tomorrow, bye!!!

    • That’s an interesting way to look at it, Hannah! We’re not sure what the length of the actual woolly worm (and not just its bands) might mean about the length of the seasons. We’ll both have to do some more WONDERing about that! :-)

  10. I love bugs! So that means I loved the video. Thank you wonderopolis for telling me about the video when we chatted after the why do dogs chase their talls video.

  11. Thanks for leaving us three great comments on this Wonder of the Day®, buglover! Did you visit the other BUG-related Wonders in the link we left for you? There are other ones we think you will really enjoy! Here is the link again: If you scroll down, you can see more BUGGY Wonders!

    Oh, and the very first Wonder was Wonder #1 – Why Are Flamingos Pink? Here’s a link to that Wonder, too: Happy Wondering! :-)

    • That’s a GREAT Wonder, Evan! We’re not sure what skills those moths might have, but now you’ve got us WONDERing more about them, too! Thanks so much for being an AWESOME Wonder Friend! :-)

    • Those are great questions, TJ! Scientists aren’t sold on the belief that woolly worms can predict the weather. Some people believe that the colored bands on a woolly worm have something to do with weather prediction, but scientists think those bands are actually indicators of the woolly worm’s age, diet, species and environment. :-)

  12. Woolly worm caterpillars can predict the weather. I read this in my science book.
    These caterpillars come in red-brown, black, and brown. These caterpillars are also very beautiful also. Great wonder and video!

    • Thanks for sharing your thoughts about woolly worms with us, Julie! We’re super glad you visited this Wonder about them! :-)

    • Great question, Kyle M! While we can’t be certain, we think the Woolly mammoth and woolly worms are connected only by their fuzzy exterior. We Wonder if we would know more if the Woolly mammoth was still roaming the Earth today… but we sure are glad you asked! :)

  13. Hi this is Matthew and I’m from Mrs. Caplin’s class I think it is cool that woolly worms have different names. The video awesome I am probably writing about the woolly worm in my notebook. I think tomorrow’s wonder will be about tape or glue because it said it just wont stick around long.

    • Hey there, Matthew! We are glad that you’ve been WONDERing about woolly worms with us! We bet you’ll do a SUPER job of writing your thoughts about woolly worms in your notebook, too! Thanks for sharing your guess about the next Wonder of the Day®! :)

    • Wow, Wonder Friend Tubbytron9000! We are very impressed with you and your friends– your club sounds like a TON of fun! We Wonder what you discuss… is it always about woolly worms, or do you talk about other insects that are squirmy, too? :)

  14. Wooly worms are so cute. Can they predict the weather? If they can that will be awesome. This is Cool5 signing out. :) :)

    • Hey there, Cool5! While many people believe that wooly caterpillars do indeed predict the weather, scientists don’t agree. However, we’d LOVE it if you read our Wonder and decided for yourself! :)

  15. We were wondering if you had any other Wonders about animals and the weather? We are learning about weather and climate right now, and we loved reading about Woolly Worms, we have a lot of them in Kansas!

    • Thanks for hanging out with us here in Wonderopolis, Gwen H.! We agree, it is fascinating! Although scientists found no correlation between the coloring of woolly worms and winter weather, they have noted that certain animals have heightened senses that allow them to predict imminent weather! :)

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Have you ever wondered…

  • Can woolly worms predict the weather?
  • What do woolly worms grow up to be?
  • Are there any other animals that can predict the weather?

Wonder Gallery

Try It Out

Ready to predict the weather? Using what you learned in today’s Wonder of the Day, spend some time outside looking for signs to interpret.

Look for insects and small animals. What are they doing? Do their actions tell you anything?

Examine plants and trees. Pick up fallen leaves. Search for evidence of squirrels or animals storing food for the coming winter.

Based on what you see in the world around you, make your own predictions about the coming winter. Write them down in a journal, or draw a picture of what you think this winter will be like and post it on the refrigerator.

Over the next few months, come back to compare your predictions to how the winter is going. Were your predictions correct? If so, maybe you have a future as a meteorologist!


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