Is 0.04 inches of rain?

Question

I keep seeing it on my weather app and I don’t know what it means.

In: Earth Science

Answer 1

Usually these are the product of the certainty of precipitation and the percentage of the forecasted area receiving it. So if there is a 40% chance of rain in the forecasted area but the system will likely only drop 0.5 inches in the affected areas and only 20% of the total forecasted area will likely get that 0.5 inches. 0.4 x 0.5 x 0.2 = 0.04

Hence the forecast averages it out for the entire forecast area as 0.04 inches.