text: how do you measure an inch of rainfall, does it depend on the diameter of the collector?   measure it in any collector. just have a standard procedure. vertical collector, have a funnel at its mouth, let water drip down from funnel to collector. measure the rain fall in mm with ur scale. if u want a detail procedure i will give u a web site. it rocks..belive in tuth..! http://www.rcn27.dial.pipex.com/cloudsrus/measurerain.html