What does "40% chance of rain" really mean?
Quick Answer: A "40% chance of rain" means there is a 40% probability that rain will occur at any point in the forecast area during the specified time. It does not guarantee rain everywhere, just that rain is likely in some parts or times within that area.
Think of it as a forecasted likelihood, not a promise. Meteorologists calculate this percentage based on models showing how likely rain is to form and where it might fall.
So, if you see 40%, that means rain is possible but not certain. Some spots might stay dry while others get wet.