eli5 How do they calculate how many inches of rain has fallen?

502 viewsOtherPlanetary Science

Where I live it does not rain a lot. When it does the news always say that it rain 1/8 of an inch or so, but I can see that my pool has increased 2 or 3 inches.

I don’t think this could be from runoff as the edges if the pool are angles away from the pool to prevent runoff from entering the pool. I have also had buckets left out where there is significantly more water than was reported.

Any reasoning for this? Could the rain vary so much that the weather station is just getting a significantly different amount of rain?

Thanks

In: Planetary Science

6 Answers

Anonymous 0 Comments

Literally they use a graduated cylinder and read how much rain collects in it. I mean, it’s a [calibrated and standardized](https://www.weather.gov/iwx/coop_8inch) cylinder but that’s essentially what it is.

Is that 1/8 the forecast, or the actual measurement taken by the weather station? And how far are you from the weather station? It’s entirely probable that the local landscape is such that you tend to get a bit more of the rain event than they do

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