The Rain sensors determines whether it is raining, and does so virtually immediately. Any rain falls on the Rain sensor's grid of gilded copper. Droplets of water conduct electricity between the grid's contact lines. A resistance measurement is carried out to detect any droplets between the contact lines. The Rain sensor is equipped with heating to prevent condensation and to dry any rain droplets quickly.

The Rain sensor should preferably be mounted on the Meteomast and connected to a Priva process computer.

The Rain sensor indicates solely that it is raining, where relevant; it does not measure the precipitation intensity. In addition, the sensor is less suitable for the identification of hail or snow.