12 Natural Weather Signs You Can Learn to Read Outdoors

Pleaset note:  Most of this info was pulled from my books Essential Wilderness Navigation or The Secret Signs of Nature.  

Long before we could pull a weather forecast out of our pocket, people had to pay attention.

They watched the sky.

They noticed changes in the wind.

They listened to insects.

They smelled the air.

They watched plants move and learned that certain cloud formations tended to show up before certain kinds of weather.

That kind of observation is something I wrote about in my children's book, The Secret Signs of Nature. One of the main ideas behind that book is remarkably simple: nature is constantly giving us information if we learn how to notice it.

That does not mean every old weather saying is accurate. Some are surprisingly good. Others contain a little truth surrounded by a whole lot of folklore.

So let's look at some natural weather indicators you can actually watch for when you're outdoors.

1. You Really Can Smell Rain Coming

Have you ever walked outside and thought, It smells like rain?

You may actually be detecting changes associated with approaching rain.

One of the smells associated with rainfall is commonly called petrichor, that distinctive earthy smell produced when rain interacts with compounds associated with soil, plants, and microorganisms.

Sometimes people notice the smell before the rain reaches them because nearby rainfall, changing winds, and increasing humidity can carry those odors through the air.

So when somebody tells you they can smell rain coming, don't immediately dismiss them.

Their nose may be picking up environmental information before their skin feels the first raindrop.

Field Observation

The next time a storm approaches, stop what you're doing for a moment.

Don't look at your phone.

Smell the air.

Then note the wind direction, cloud cover, humidity, and how long it takes before the rain arrives.

That is how observational skill develops: notice something, test it, and remember what happened.

2. Count the Seconds Between Lightning and Thunder

This one is wonderfully simple.

You see the lightning first because light reaches you much faster than sound.

When you see a flash, start counting the seconds until you hear the thunder.

Divide that number by five to get the approximate distance to the lightning in miles.

If you count:

• 5 seconds = about 1 mile

• 10 seconds = about 2 miles

• 20 seconds = about 4 miles

• 30 seconds = about 6 miles

The National Weather Service uses the same basic relationship.

But Don't Use This to Decide Whether You're Safe

This is where field knowledge needs to be separated from a neat nature experiment.

If you can hear thunder, you should already be seeking appropriate shelter.

Lightning can strike well away from the portion of the storm producing rain. The National Weather Service recommends getting inside a substantial building or fully enclosed vehicle when thunder is heard and remaining sheltered for at least 30 minutes after the last thunder.

Knowing how far away lightning is can help you understand what is happening.

It should never become an excuse to stand around watching the storm get closer.

3. Crickets Can Tell You the Temperature

Here's one that sounds like folklore but has some excellent science behind it.

Crickets chirp faster as temperatures rise and slower as temperatures fall.

This relationship is so well known that it's called Dolbear's Law, named for physicist Amos Dolbear.

One simplified method is:

Count the number of cricket chirps in 15 seconds and add 40.

The result gives you a rough estimate of the temperature in degrees Fahrenheit.

For example:

25 chirps + 40 = approximately 65°F.

NOAA discusses this relationship specifically, although species matters and it should be considered an estimate rather than a precision thermometer.

Are Crickets Predicting Barometric Pressure?

This is where I would be careful.

You may hear claims that cricket activity predicts falling barometric pressure or approaching storms. Behavior may change with environmental conditions, but the well-established relationship is between chirp rate and temperature, not barometric pressure.

That's still pretty remarkable.

You're standing outside listening to a living thermometer.

4. Watch for Leaves Turning Their Undersides Up

This is another classic observation.

Before some storms, you may notice trees appearing lighter or almost silvery because you're suddenly seeing more of the undersides of their leaves.

People sometimes explain this by saying:

"The falling barometric pressure makes the leaves turn over."

That's probably giving atmospheric pressure too much credit.  It is a combination of that and changing wind conditions.

What you're often seeing is vegetation responding to changing wind conditions associated with approaching weather. Gusty or shifting winds can expose the paler undersides of leaves.

Some plants also alter leaf orientation in response to heat and water stress, so an overturned leaf by itself isn't a weather forecast. University of Minnesota Extension, for example, documents plants flipping or changing leaf orientation under environmental stress.

Look for a Pattern, Not One Leaf

One branch moving means very little.

Hundreds of leaves suddenly showing their undersides while the wind shifts, clouds build, and the air changes?

Now you're collecting multiple pieces of information.

That is far more useful.

5. Wispy Cirrus Clouds Can Signal Changing Weather

Those thin, feather-like clouds high in the sky are called cirrus clouds.

They are mostly composed of ice crystals.

A beautiful blue sky with a few streaks of cirrus may seem like perfect weather, but those clouds can sometimes be an early indication that conditions are changing.

NOAA lists cirrus clouds as an indicator that a change in weather may be on the way.

This is one of those signs worth watching over several hours.

Do the wispy clouds disappear?

Or do they gradually increase and begin covering more of the sky?

The trend matters more than the individual cloud.

6. A Halo Around the Sun or Moon Can Mean Moisture Is Moving In

This is one of my favorite signs because once you learn it, you begin noticing it everywhere.

Sometimes you'll see a large ring surrounding the sun or moon.

That halo is produced by light interacting with ice crystals in high-altitude clouds, commonly called cirrostratus clouds.

Cirrostratus often develops ahead of an approaching weather system. NOAA notes that this cloud type can indicate rain or snow arriving within roughly 24 hours.

That doesn't mean every halo guarantees rain at your exact location.

Weather doesn't work like a vending machine.

But a halo is absolutely worth adding to the other information you're collecting.

7. Watch Cumulus Clouds Grow Upward

Those puffy cotton-ball clouds on a warm afternoon are cumulus clouds.

Small cumulus clouds generally aren't concerning.

What should catch your attention is rapid vertical growth.

When those clouds start getting taller and developing that cauliflower appearance, you're watching convection -- warm, moist air rising through the atmosphere.

A significantly vertically developed cumulus cloud is called towering cumulus, or cumulus congestus.

Given enough moisture, instability, and lift, it can continue developing into a cumulonimbus cloud: a thunderstorm.

Watch the Same Cloud for Ten Minutes

This is a fantastic nature-awareness exercise.

Pick one cumulus cloud.

Notice its highest point.

Look away for five or ten minutes.

Then look again.

If that cloud appears to be exploding upward, the atmosphere is telling you something.

8. A Sudden Cool Wind Can Arrive Before the Rain

You're hiking on a hot afternoon.

The air has been fairly still.

Then suddenly the wind picks up.

The temperature seems to drop.

Leaves begin moving.

And maybe you can smell moisture.

Pay attention.

You may be feeling a gust front, the leading edge of cool air spreading outward from a thunderstorm.

The National Weather Service notes that a gust front can arrive several minutes before the actual precipitation and is commonly experienced as a sudden change to cooler, gustier winds.

This is one of the better immediate storm indicators because you're no longer looking at something happening miles above you.

You're physically feeling the storm's outflow reach your location.

9. "Red Sky at Night" Has Some Science Behind It

You've probably heard:

Red sky at night, sailor's delight.
Red sky in morning, sailor take warning.

There are limitations, but this is not complete nonsense.

In the middle latitudes, weather systems commonly move from west toward east. Under the right conditions, the position of clearer air, clouds, moisture, and suspended particles relative to the rising or setting sun can give you clues about which type of air may be moving toward you.

NOAA actually discusses the old saying and explains why it can sometimes work.

It's a clue.

Not a guarantee.

That distinction should apply to nearly every natural weather sign.

10. A Rainbow Can Tell You Where the Rain Is

A rainbow isn't just pretty.

It tells you something about the location of precipitation.

A rainbow forms opposite the sun as sunlight interacts with water droplets in the atmosphere.

That means your position, the sun's position, and the rain's location are connected.

Historically, observers even used morning and evening rainbows as crude indicators of where showers were located and potentially moving. NOAA's historical weather records contain versions of this observation going back generations.

Instead of simply admiring the rainbow next time, turn around.

Find the sun.

Determine direction.

Now you're reading the landscape and the sky together.

11. Falling Barometric Pressure Really Is Useful

This one requires an instrument, but modern watches, phones, handheld weather meters, and traditional barometers make it easy to observe.

The important thing isn't simply whether pressure is "high" or "low."

Watch the trend.

Is it rising?

Steady?

Falling?

The National Weather Service defines pressure tendency specifically by whether atmospheric pressure has been rising, falling, or remaining steady over a period of time. A persistent fall in pressure can accompany an approaching low-pressure system or front and deteriorating weather.

Establish Your Own Baseline

This is where tracking and weather observation have a lot in common.

One measurement doesn't tell you much.

Repeated measurements show change.

If you have a watch with a barometer, check it when you arrive at camp.

Check it a few hours later.

Check again before bed.

Now you're looking for a pattern rather than staring at a number.

12. The Best Weather Sign Is Usually Several Signs Together

This may be the most important one.

Don't build a forecast around one overturned leaf.

Don't assume rain is coming because you smelled something earthy.

Don't call off the family camping trip because you saw a cirrus cloud.

Instead, learn to stack indicators.

Imagine you're outside and notice:

Sign One

Wispy cirrus clouds have been increasing all afternoon.

Sign Two

Later, a halo develops around the moon.

Sign Three

Your barometer has been steadily falling.

Sign Four

The next day, cumulus clouds begin rapidly building vertically.

Sign Five

The wind suddenly shifts and cools.

That tells you considerably more than any single observation.

And that's really what reading nature is about.

Nature Doesn't Give Us Apps. It Gives Us Patterns.

I have nothing against technology.

Use a good weather forecast.

Check radar.

Pay attention to National Weather Service watches and warnings.

Carry the tools that make sense for what you're doing.

But don't allow those tools to stop you from developing your own awareness.

Look at the clouds.

Feel the wind.

Listen to the crickets.

Notice which side of the leaves you're seeing.

Smell the air.

Watch what changes.

That's part of the idea behind The Secret Signs of Nature and a big part of what we teach at Nature Reliance School.

The goal isn't to become some sort of human weather station.

The goal is to become a better observer.

Technology can tell you a storm is approaching.

I'd also like you to be standing outside thinking:

Yeah. I can see it coming.

Come join us where the best classroom has no walls.