Dandelions And 5 More Plants That Predict The weather

Did you know that there are plants that predict the weather? Dandelions and these five other plants can tell you when it may rain, the temperature outside, and more!

Dandelions are plants that predict the weather.
Dandelions open when it is dry outside and close up when it is wet.


Despite their reputation as pesky lawn weeds, dandelions are also good indicators of rain—especially since you’re likely to find them wherever you go! Like pimpernels (see below), these herb-flowers close when they detect moisture and reopen when the weather dries. Learn more about dandelions.

Scarlet Pimpernel and Dandelions close up in the rain.
Scarlet Pimpernels fold up in the rain.

Scarlet Pimpernel

The scarlet pimpernel is such a good prognosticator of fair and foul weather that it has been nicknamed the “poor man’s weather glass.” Its blooms remain open in full sun, but when skies turn cloudy or humidity reaches about 80%, they fold up like little rain-shy umbrellas. They do this to keep their pollen dry and their nectar from being diluted.  

Pinecones and dandelions open when it is dry outside.
Pinecones open up when it is dry outside.

Pine Cones

Even fallen pine cones can be used to predict the weather. If the air is dry, pine cones fan out their scales, resembling mini-Christmas trees. If, however, there is a rise in humidity or if rain is in the air, their scales will clamp tightly shut, overlapping one another. This finicky behavior has to do with seed dispersal phenology.

During dry weather, seeds nestled deep within the pine cone are looser, lighter, and more easily carried off by winds. But when the weather is damp, seeds are prone to clumping together and won’t travel as far away from home.

Earthstar fungi open up in damp conditions.
Earthstar fungi open up when it is wet outside.


Contrary to dandelions and other plant prognosticators, earthstar (Astraeus hygrometricus) is observed during gloomy weather and predicts when conditions will clear. This fungus—which resembles a brown mushroom surrounded by a skirt of leathery “petals”—remains open during rainstorms (raindrops help disperse its spores), so when these “petals” curl up and enclose the center spore sac, you can expect rain to end soon. Learn more about Earthstars and other fungi at the NationalParkService.gov.

Seaweed is plump when it is humid.
Seaweed plumps up when it is humid.


If you’re a coastal dweller, be sure to keep an eye on any surfaced seaweed. Pay particular attention to what this humidity-sensitive plant does after it washes ashore and lies exposed to the air. When it plumps up, that’s an indicator the weather is damp and muggy. (This is likely a result of the plant being coated with sea salt, which is hygroscopic and attracts moisture.)

If, however, surfaced seaweed appears shriveled and dehydrated, take it as a sign that conditions are dry.

Rhododendrons are plants that predict the weather.
Rhododendrons close up if it’s cold outside.


Curious to know the current air temperature? Look to the nearest rhododendron shrub. When temperatures dip to 32 degrees Fahrenheit (freezing), a rhododendron’s long, leathery leaves begin to droop and gradually curl inward. And at 20 degrees and lower, their leaves are tightly curled, like cigars, and point straight down to the ground.

This behavior is basically a defense mechanism. Since rhododendron plants aren’t able to soak up as much groundwater when soil is frozen, they curl their leaves so as not to lose water through them. However, once temperatures creep back above the freezing mark, rhododendron leaves fully unfurl and return to their flat, oval shape.  

Join The Discussion

Did you know any of these fun facts about dandelions and other plants that predict the weather?

What is one thing that you learned today?

Let us know in the comments below!

Print Friendly, PDF & Email
Farmers' Almanac - Hair coloring
Tiffany Means

Tiffany Means is a freelance writer and a degreed meteorologist. She specializes in weather forecasting and enjoys making the subject of weather (and the science behind it) more relatable. She currently resides in the Blue Ridge Mountains of North Carolina.


Oldest Most Voted
Inline Feedbacks
View all comments

This further supports my belief? understanding? that in the hours before it rains, a particular plant opens up, or lets its pollen fly, and said pollen makes me sneeze. Has happened all of my life living in this part of the central valley of California.


Found this so interesting, thanks! I will be looking forward to observing these plants a lot closer.

Kat Dancer dancer

dandilions were brought to our shores by the pilgrims. not only are every part of the plant medicine,it breaks up clay soil. I love them…


Tiffany Means, thank you for sharing all of those interesting tidbits! Through the years, I’ve noticed dandelions opening & closing, but for some reason, I didn’t think to question “Why???” in regard to this particular phenomenon. You’ve enlightened me & I’m grateful! 😊

Farmers' Almanac

Hi Jennifer, We’re so glad to hear that you learned something new! Come back and see us again soon. 🧡

Jacquelyn Gaines

Thank you, Ms. Means, for this information about nature and how our creator gave us all we need to survive on this planet. Jacquelyn

Plan Your Day. Grow Your Life.

Get money-saving tips, weather updates and more! Sign up today.