When the forecast says 30% chance of rain. What exactly does that mean?

Posted at 10:18 AM, Apr 26, 2022
and last updated 2022-04-26 10:18:42-04

RICHMOND, Va. -- When you're watching the CBS 6 forecast on TV or reading the forecast on the CBS 6 app, the chance of precipitation is often included. This is called the “probability of precipitation” and is sometimes abbreviated as POP. It is expressed in a percentage.

So, if there’s a 30% chance of rain, what does that mean?

It means where you are, the odds of you seeing rain is 30%.

Think of it as if someone were to say, “my schedule is busy, so there’s only about a 30% chance I might make it to the baseball game."

The chance of precipitation does not indicate the intensity of the forecasted precipitation.

A 20% chance of a pop-up thunderstorm could still yield heavy rainfall.

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It also does not indicate for how long the rain might fall.

An 80% chance of rain does not mean it will rain 80% of the day.

The chance of rain in the summer is low many days, since thunderstorms are so widely scattered.

At CBS 6, we add other details in addition to the chance of rain.

If certain sections of the viewing area have a better chance of rain, we will show a map that indicates where those higher rain chances are focused.

We also mention when the chance of rain is most likely, such as “there’s a 100% chance of rain Tuesday morning.”

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The percentages shown on our 7-day forecast are for metro-Richmond. Our CBS 6 Weather Authority app will show you your chance of rain if you live elsewhere, or if you are traveling across the region.


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