What's POP, anyway? Viral TikTok video starts a discussion

It's a viral TikTok video that comes with a meteorology lesson.

Earlier this week, TikTok user Scarlett Moffatt posted a video about her weather app that resonated with users, racking up around 350K 'likes' and counting.

"I just found out that on the weather app, when it says 30 per cent rain, I thought it meant 30 per cent chance of rain," Moffatt says.

"It doesn't mean that. It means 30 per cent of your area will be covered in rain."

While Scarlett is on the right track, we thought we’d break down POP and how you can use it to interpret the forecast.

LET'S TALK POP

The POP, or probability of precipitation, feature is commonly found on weather apps and forecasts. You can see it on our forecast pages as well, in a column that looks like this:

POP

Chris Murphy, a Weather Network broadcast meteorologist, says POP functions like an added tool to help plan the day.

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When an area has an 80 percent POP of rain or snow in the morning, for example, it doesn't mean that there will be precipitation for 80 per cent of the morning, or that 80 per cent of the area will be covered in rain or snow.

"It simply means that if this exact same storm system went through 10 times, 8 out of 10 times it would bring you precipitation within that forecast period," Chris says.

If the POP drops to 30 per cent in the afternoon, "there's only a 3 out of 10 chance you'll get any precipitation from this scenario."

So -- while meteorologists can't tell the future, they can use probability to predict outcomes, not unlike what we see during elections, sports finals, and financial investments.

Thumbnail image courtesy Photo: Erik Witsoe