Most rain gauges measure the precipitation in inches or centimeters.
Types of rain gauges include graduated cylinders, weighing gauges, tipping bucket gauge, and simple burried pit collectors. Each type has it advantages and disadvantages for collecting rain data.
Rain gauges have their limitations. Attempting to collect rain data in a hurricane can be nearly impossible and unreliable (even if the equipment survives) due to wind extremes. Also, rain gauges only indicate rainfall in a localized area.
See also: disdrometer