A method for determining a rate of rain falling on a surface. As rain falls and strikes the surface, vibrations are generated on the surface. The vibrations are sensed and a vibration signal is generated, the vibration signal being proportional to the vibrations of the surface. The vibration signal includes peaks. The peaks of the vibration signal are determined. The time intervals between the peaks are then determined. Using the time intervals, a number n1 of timer intervals that occur between a first time and a second time are counted. A number n2 of time intervals that occur between the second time and a third time are also counted. The rain rate λ is then determined using an equation that is derived from a point process equation and utilizes n1 and n2.