People seriously confused after realising what ’40% chance of rain’ actually means

Have you ever wondered what the percentages on the weather apps actually mean when it comes to rain?

Some people are only just realising how it’s worked out, after a meteorologist broke it down into a simple explanation - while others have been left more baffled than before.

Often when you see the figure, for example 40% - you will assume it means either that 40% of the area will get rain or that it will rain 40% of the time.

But actually, none of these huge misconceptions are true and there’s actually quite a bit of maths involved when it comes to the weather.

Ariella Scalese, a meteorologist at Accuweather, took to Instagram to offer an explanation to people after constantly getting asked the same question.

In a video shared to the social media platform, she said: “Oh, if I had a dollar for every time I got asked that question. Let’s clear up what that actually means.”

Scalese said that it means that ‘there’s a 40% chance that at any point in the forecast area will see rain during the specified time.’

Still confused? Yep, us too.

The meteorologist continued: “When we talk about the probability of precipitation, we’re talking about the likelihood of getting at least one hundredths of an inch of rain.

“That’s enough to form a small, underwhelming puddle. Forecasters come up with the number by multiplying two factors. Number one is certainty.

“How sure are we that rain will form or will move in the area? And number two coverage. How much of the area is expected to get rain?”

She added: “Let’s get an example. If a forecaster is 80% sure it will rain but only expects it to cover 50% of the area, that equals a 40% chance of rain.

“Or, if they expect rain to cover the whole area but are only 40% sure it will reach us, that also gives a 40% chance of rain.”

Finally, Scalese signed off by recommending people always look ‘beyond that percentage for making their outdoor plans.’

She advises looking at any description that comes with the stats, as these often go into more details about timings.

Despite the video being intended as a helpful resource, people seem more confused than ever after watching it.

And we don’t blame them - it is quite tricky to get your head around.

One user penned: “So it might rain or it might not? Got it.”

Meanwhile another simply joked: “There’s a 70% chance that I didn’t understand any of that.”

“Why not display both numbers instead of multiplying them and showing a single one that conveys less information?” questioned a third Instagram user.

And a fourth agreed: “Why not give us the 2 parameters instead of a number that gives us no idea of coverage and chance?”

Opting for a more brutal reply, someone else wrote: “Perhaps the profession needs to do a better job explaining things if you get asked this so many times….”

“So basically we have no idea if it will rain but it might,” quipped another social media user.

Others added: “I'm more confused after this explanation” and “100% chance you just made this more confusing for me.”