How to calibrate a tipping rain gauge.

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[looney2ns]

I have a tipping rain gauge that has been in service for 7 years. What would be the proper way to check it and calibrate if I find it needs tweaking?
It's a 6"dia top, and I use inches.
Thanks!

[niko]

OK, so the opening is 6" diameter, that makes the area of the opening pi * (3)² = 3.142 * 9 = 28.278 sq inches.

If one inch of rain falls then 28.278 cubic inches of water would pass through the gauge.

28.278 cubic inches = 15.7 fluid ounces (US) or 463.39 millilitres (ml).

So if you measure that amount of water and drip it very slowly through the gauge, it should register one inch of rain. For a more accurate result drip a multiple of that amount of water, 2 or 3 inches, but be careful not to exceed the maximum rain rate that the gauge can handle.

[looney2ns]

Thank you very much. I appreciate the calculations!