# What Does 20 Chance of Rain Mean?

#### June 1, 2023

There’s been a lot of confusion this summer about what “chance of rain” means on TV and in weather apps. This confusion can be attributed to a viral TikTok video that misrepresented what a chance of rain actually is. Chance of rain, also known as Probability of Precipitation or PoP, is the likelihood that a point in a forecast area will experience measurable precipitation during a certain time period. It’s calculated by multiplying two things: 1) the confidence a forecaster has that rain will happen, and 2) how widespread they expect that rain to be. Let’s say a forecaster has 100% confidence that it will rain and they are expecting 80% of their forecast area to get rain. The chance of rain will be (1 x 0.8), which is equivalent to a 70% chance of rain.

However, chances of rain don’t tell us anything about how much rain will fall or how long it will last. That’s why it’s important to watch for a phrase like “scattered showers” or “patches of rain” in the forecast, as these indicate that it will likely be very light.

### Mission

Tornado Dave is the best place to learn more about severe weather and climate science. He's a veritable tornado of information, and he loves nothing more than educating others about the importance of being prepared for extreme weather events. Make sure to check in with Tornado Dave often, as he's always updating his blog with the latest news and information!
hello world!