rainfall gauge

Instrument used to measure precipitation, usually rain. It consists of an open-topped cylinder, inside which there is a close-fitting funnel that directs the rain to a collecting bottle inside a second, inner cylinder. The gauge may be partially embedded in soil to prevent spillage. The amount of water that collects in the bottle is measured every day, usually in millimetres.

When the amount of water collected is too little to be measured, trace rainfall is said to have taken place. Snow falling into the gauge must be melted before a measurement is taken.