How To Know That It Is Going To Rain – Without The Assistance Of A Professional Weather Forecast

How To Know If Its Going To Rain heading

We all rely on weather forecasts to tell us what the weather will be like in the future. But what if you have no access to any kind of weather service. Will you still be able to make your own forecast, especially tell if it's going to rain or not?

You probably heard the stories of old people saying it is going to rain because "they can feel it in their bones". And when your mum or grandmother complained about the thousands of ants invading the house because "there is probably some rain on the way again"

They are actually all right, and there is an explanation for it. But is it possible to really tell whether significant changes in weather,  especially rainfall is on its way?

Actually you can. By observing your surroundings, especially different elements of the weather your senses are able to pick up, you will be able to get a very good idea of how the weather will change in your vicinity in the immediate feature.

By observing the following 5 elements that can all be good indicators of changes in weather, you will be able to a make surprisingly accurate forecast of how the weather will change in the coming hours:

  • Cloud Formation
  • Humidity  
  • Smell
  • Wind
  • Animal & Insect Behavior

Cloud Formation

One of most visible ways of telling how the weather will react is by observing the clouds. Knowing the different types of clouds will definitely help you make more accurate assessments, and its actually not as difficult as you may think. More on that shortly. 

It is not just the different types of clouds that will determine the weather. By also observing their altitude and colour, you will be able to get a good indication as to when to expect possible rainfall, as well as how heavy it may be.

Cloud Colour & Height

As you know, clouds are nothing more than moist air that has risen high enough to cool down, causing condensation and small raindrops to form. The amount of raindrops/moisture present in a cloud has a direct effect on its colour.

Cumulonimbus Clouds

Cumulonimbus Clouds

In general, the darker the cloud, the more moisture it contains. That is why rain-bearing clouds like cumulonimbus and nimbostratus clouds have a dark gray, sometimes almost black base. This normally indicates imminent and heavy rains.

Very light-coloured clouds, like cirrus clouds normally indicate clear weather for the foreseeable future. If they form out of nowhere in an otherwise clear sky, it may indicate possible rain within 36 hours, but does not indicate any imminent rainfall and they carry very little moisture themselves.

The height of a cloud has two aspects to it that determine its behavior. The actual height of the cloud base (altitude) and Cloud density (vertical extent).

Clouds with their bases high in the air (cirrus, cirrocumulus and cirrostratus) are generally not associated with rain, whereas low-laying clouds are more commonly associated with rainfall. This is just very rough indication though. 

A much clearer indication of how a cloud will behave, is the extent of the cloud density. Clouds like cumulonimbus clouds with a low base in the troposphere but with a massive vertical buildup, almost always indicate some kind substantial rainfall. 

In contrast, very thin clouds (clouds with a small vertical extent) are normally very unlikely to result in rainfall by themselves.

The best way to make a accurate assessment of approaching weather, is by looking at the cloud colour, height and density combined. This way you will be able to get the most complete picture of what to expect.

Cloud Types

Being able to identify the different types of clouds and their characteristics, will make it much easier to know how a cloud formation will affect you and potentially how much or how little rain you can expect.

Lets quickly run through the list of most important cloud types, from the ones potentially producing the most rainfall, down to those producing none.

Nimbostratus

These mid to low-lying dense cloud formations are synonymous with large-scale rainfall. They are characterized by their dark colour and are so dense that they can completely block out the sun. Depending on the wind speed, they can produce persistent rainfall for sustained periods of time.

Cumulonimbus Clouds

Although they have a fairly low-lying base, these clouds build up vertically to spectacular heights of up to 39 000 feet (12 000 meter). They are commonly referred to as thunderclouds and are associated with thunderstorms and very heavy rainfall. 

Due to the huge vertical buildup in the these cloud systems, they contain a lot of moisture, which can lead to downpours so heavy that flash flooding can occur. Although intense, the rainfall normally doesn't last very long and normally dissipates within 20 minutes.     

Altostratus Clouds

These mid-level clouds are characterized by a large featureless blanket of clouds that can spread for thousands of square miles. (This is the cloud type that comes to mind when people talk about a typical dreary winters day).  

Altostratus clouds are normally associated with widespread light rain. Although they don't normally produce heavy rainfall by themselves, they are often seen as precursors for nimbostratus clouds.

Cumulus Clouds

Probably the most well-known (and loved) clouds around the world, are the cumulus clouds. These well-defined cotton-like clouds are low-level clouds that is normally an indication of pleasant and clear weather.

Cirrus Clouds

Cirrus Clouds

Cirrus Clouds

As already mentioned, these streaky white clouds are formed higher up in the atmosphere and are considered high-level clouds as a result. They contain mostly light ice crystals and don't pose any danger of rain themselves. They are often seen by meteorologists that rain might be expected within 36 hours.

Obviously there are many other cloud types, and sub-categories of the clouds just mentioned. They all fall within the spectrum of the 5 cloud types mentioned in this section though, so for the sake of this article we don't need to go into further detail.

Being able to recognize the different clouds as they approach will help you to get a better picture of what to expect in the coming hours.

Humidity

Approaching rain is almost always preceded by an increase in humidity (the amount of moisture in the air). There are several ways you can detect an increase in humidity. You can find tell-tale signs on both your own body, and in the environment around you:

  • "Wet" Smell: We all know the familiar "wet" smell that follows a downpour. A similar smell, just less powerful can be detected before the arrival of rain clouds.
  • Changes In Hair Structure: You may start to notice that your normally smooth straight hair suddenly starts feeling a bit frizzy, which is a direct result of more moisture in the air.
  • Indicators From Nature: Nature are sometimes the best possible indicators of changes in weather. The pine cones on pine trees automatically closes to protect themselves when the air becomes moist. The leaves of maple trees starts curling. In areas with high humidity, wood starts to swell  and warp. Even smelling the flowers will help you to detect humidity. Normally the smell of flowers are more powerful as scents are much stronger in moist air.

There are some other less obvious indicators of a buildup of moisture in the air, but the three just mentioned are some of the most obvious and easily detectable ones.

Smell

Stronger Scent Of Flowers

Yes, you are reading this right. The smells in the air can give you a very good indication of approaching weather. I already touched on the strong smell of flowers and the typical "wet smell" that is associated with the rise in humidity preceding rainy weather.

There are further indicators however, especially from nature, that present themselves in the form of strong scents that points to approaching rainy conditions:

  • "Compost" Smell: A smell very reminiscent of decaying compost is very evident in the air, which is a result of plants releasing their waste.
  • Swam Gasses: If you happen to live near a swamp, you may become very aware of swamp gasses that the low-pressure system allows to rise and drift with the wind. (These gasses have a smell very similar to rotten eggs, so unfortunately not a very pleasant experience.)

As you start becoming more aware of these smells associated with rainy weather on a regular bases, you can actually pick up indications of changes in weather conditions without even looking or going outside.

Wind (Or Lack Of It)

One of the strongest indicators of approaching rain, is the picking up of wind or, a change in wind direction. There is small catch however. The wind direction that brings with it the rain-bearing clouds, depends completely on where on the planet you are located. This means you have to know which winds are associated with rain or bad weather in your region.

In an area in the Northern Hemisphere, the wind will blow in completely the opposite direction than in an area in the Southern Hemisphere. If you have been living in a town/city for some time, you will most probably be familiar with the wind direction associated with rainfall. (Or you can find out from neighbors or older people very familiar with the region.)

Similarly, a lack of air flow (wind) very often points to approaching rain. Especially in a normally windy area, if the wind suddenly dies down and everything become very still, it more often than none is literally the calm before the storm. This is direct result of the low-pressure system that moves in and pushes of the normal wind patterns out of an area.

​Animal & Insect Behavior

Ant Invasion

Behavior of animals and insects that are out of the norm, can also be a clear indication of rain or stormy weather. This is because all of them have senses far superior to humans or even some instrumentation.

Thousands of years of evolution helped them to develop these lifesaving senses. They are able to pick up atmospheric changes and act long before the actual weather arrives. Here are just a few examples of animals/insects and their behavior you can watch out for:

  • Ant Invasions: This probably one of the most well-known phenomena throughout the world. Many of you have experienced your homes being invaded with ants sometimes more than a day before heavy rains arrive.   
  • Bird Behavior: If you are living in an area with plenty of bird activity, you may already be familiar with this behavior. Very often, before rain or stormy weather arrives, bird activity dies down very quickly. As they are able to sense the approaching weather conditions long before we can, they seek shelter and stop flying around.
  • Livestock Behavior: If you live on a farm or in a rural area, you may be surprised how even more "domesticated" animals like cattle are able to pick up on an approaching storms long before there are any physical evidence. Very often, before a rain storm arrives, you will see a herd of cattle huddle together and lie down for protection in the middle of a field.

These are behaviors that have been well documented and proven over the years, and are pretty reliable indicators of approaching bad weather. 

Then off course you get a quite a few unsubstantiated claims, like spiders coming down from their nets, frogs sounding louder before a storm, and dogs eating grass. (Yep, I am also not so sure about that last one.)

The point is, by paying attention to how the wildlife and even some domestic animals around you suddenly change behavior, you can be provided with valuable information about approaching changes in weather conditions.

Conclusion

So yes, you definitely will be able to make a fairly accurate forecast of what the atmospheric conditions will be like at your location within the coming hours. As discussed, you achieve this by looking at the cloud formations, smelling the air, observing animal behavior, paying attention to the wind, and assessing the humidity.

Even better. By taking all these elements and combining all the "data" you get from them and analyze them together, you should be able to form an even more accurate picture of how the weather will behave for sometimes up to 12 hours.

Will you be able to make an accurate 24 hour forecast? Probably not. Will you be able to make a 5-day forecast? Off course not. (except if you have your own personal weather satellite orbiting the earth. Most home professional weather stations are not even able to forecast beyond 24 hours!)

But having the ability to judge how the weather conditions around you may change, is a pretty handy skill set to have.   

Feel free to leave me any comments, questions or suggestions, and I will get back to you as soon as possible.

Remember to join my  Mailing List  to be informed whenever a new article is released, and share new developments and helpful hints & tips.

Until next time, keep your eye on the weather!

Wessel

Wessel Wessels
 

Lifelong weather enthusiast. Interest in all things weather-related, and how global climate and local weather interact. Home weather station owner for almost 2 decades, but still learning and expanding my knowledge every day. Keen on sharing my knowledge and get more people involved and interest in both their local weather and how it interacts with climate on a global scale. Love sharing my knowledge on home weather stations, how they work and the many ways you can use them to your advantage. All in all, just a bit of weather nerd.

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