A very common phrase meteorologists use is just blowing peoples’ minds now that they know what it actually means. Several people have taken to TikTok to explain the truth behind when weather presenters say “there's a 40% chance of rain in your area”…and the answer is shocking for many.
So, here’s the deal…if a meteorologist on the news says, “there's a 40% chance of rain,” she doesn’t mean that there’s a 40% chance it will rain. What she means is that there is a 100% chance that it’ll rain in 40% of the area. The result of this calculation is known as “probability of precipitation” or “PoP”.
The point of PoP is to give a single number that takes two things into consideration – how likely it is to rain and how widespread the rain will be. But unfortunately for many viewers, PoP continues to be totally misunderstood, hence the confusion on TikTok.
How PoP is calculated
- To get the PoP, you need to multiply “C” (how “confident” a meteorologist is that it will rain) and “A” (the “amount” of an area that will get rained on).
- For example, if a meteorologist is 50% confident that 60% of an area will get rain, they’d multiply 0.5 x 0.6 and get a PoP of 0.3 or 30%.
Because of this confusion, many meteorologists have abandoned revealing the PoP score altogether…although perhaps they should consider bringing it back now that we actually know what it means!