4 ms·

I've always interpreted it as the percentage of time it will rain, i.e. if it says 50% chance from 7 to 8, it will rain during about 30 minutes of that interval

I've always interpreted it as the percentage of time it will rain, i.e. if it says 50% chance from 7 to 8, it will rain during about 30 minutes of that interval and not rain during the other 30 minutes. (equivalently, you could say it's the % chance that it will be raining if you choose a given instant X in the interval). I've never read an official interpretation but that seems to fit reality (where I live) quite well.

nindalf 11y ago
50% means that they ran the simulation say 10 times and in 5 of those simulations there was rain in the area. How to translate that to real life - you should probably carry an umbrella if you don't like getting wet. Also interesting to note that weather presenters usually bump up the probability of rain by 10-20%, because people complain about false negatives (rained when it was predicted not to) rather than false positives (didn't rain when it was predicted to). If you're interested in a good intro to this topic I recommend the chapter on weather prediction from The Signal and the Noise by Nate Silver. Its a fascinating read.