What does a ‘30% chance of rain’ really mean? How meteorologists determine rain chances

For example, a 30 percent chance of rain may mean 100 percent confidence that only 30 percent of the forecast area is going to get rain.

Heather’s Weather Whys: What does a 30% chance for rain mean?

Missing In Arkansas: Brandon Barron

what does 30 chance of rain mean

what does 30 chance of rain mean

Answering TikTok: What does a ‘30% chance of rain’ actually mean?

“I thought, 100%, that when they said there was a 30% chance of rain, that it meant that there was a 30% chance that it was going to rain,” she said in the video, which went viral on TikTok and Twitter. “I never, ever, ever knew that it meant that theres 100% its going to rain, and its going to be in 30% of your area.”

“We want it to be easy,” he said. “Take it at face value. Your probability of precipitation is simply the chance of rain on a scale of zero to 100, if its warm enough for rain, at some point in the forecast time.” And, he added, “the same applies to snow, freezing rain or sleet.”

What Does a 30% Chance of Rain Really Mean?

It may seem like a simple phrase, but believe it or not, it’s a simple phrase that means something different to different people. For instance, some people believe that a 30% chance of rain means that 30% of the area will see rain while others think that it will rain for 30% of the time. Others simply believe it’s just the odds of seeing rain. None of these are bad guesses and the last one is actually the closest, but there’s a lot more that goes in to that chance of rain.

Many people think that the higher the chance of rain the heavier that rain will be…that is incorrect. The chance of rain does not factor in precipitation intensity. For Instance, it is possible for some areas to see over an inch of rain on a day with only a 30% chance of rain while only seeing a tenth of an inch of rain on a day where the chance of rain is 100%.

– When we say that showers or thunderstorms are “likely”, it means that most of not all of the region will see precipitation at some point during the day. These are days you should expect rain and you’ll want to have the rain gear on hand, but don’t forget….just because rain is likely to fall doesn’t mean you’ll see a lot of it!

– When we say “isolated showers” or “isolated thunderstorms”, it means that most locations will get through the day without receiving a drop of rain or a seeing a flake of snow. One shouldn’t expect rain in these instances but don’t be surprised if your recently washed car ends up with a few water spots. Anytime the chance of rain is at 10% or lower we typically leave it out of the forecast.

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