When you check the weather app on your phone, seeing 30% rain means that there's a 30% chance of it, right? Well... not exactly!
We've all fallen victim to seeing a low percentage of rain, dressing for dry weather, and then finding ourselves battling the elements later on.
However, the real meaning behind the percentages may change how you approach your outfits for the day, or whether you go for that outdoor picnic.
The percentage doesn't mean a chance of rain but instead means the percentage of your area that'll be covered by it.
Gogglebox star Scarlett Moffatt, 32, has taken to TikTok to show her surprise at finding out this information, and it turns out she isn't alone!
The caption reads: "They should teach you how to read weather apps in school and that 🤣 🌧."
During the video, she reveals her shock at this life-changing information. "All this time I've been caught in the rain and people are like, 'Why haven't you brought a jacket?' and stuff like that," she says.
"It's because I've just found out that on the weather app when it says '30 percent rain', I thought it meant 30 percent chance of rain.
"It doesn't mean that. It means that 30 percent of your area will be covered in rain," she explains as she gestures that her mind has been blown.
Users in the comments were also shocked, with one saying: "You’re joking!!! ? ? ? I’m today’s age to know this now! 🤯😂😂😂."
Another user said: "No way???? Is this actually true??? I swear I also thought it was 30% chance 😂😂," and a third added: "Oh my god my whole life has been a lie."
A fourth person thought it meant something else entirely: "So is it really just me that thought it was the power of rain from drizzle to hail 😂😂"
Doubts have been cast on these revelations, with Taste Of Home going into a bit more depth: "Meteorologists aren’t in agreement on how to measure the Probability of Precipitation, aka that little percentage of rain on your weather app.
"Some use a formula for it — PoP = C x A, where C stands for confidence and A stands for area. So if there’s a 50% chance of rain in 80% of a given area, your probability of rain becomes 40%."
Whatever the percentage actually means - let's just all agree to wear a coat in the future!