Abstract: A precipitation sensor including: an outer housing having a top portion and forming the first cavity, and inside of the first cavity including a variable-permittivity medium that is exposed at a top of the first cavity; first and second conductive plates extending along at least part of a vertical dimension of the first cavity, the first conductive plate and the second conductive plate disposed so that the variable-permittivity medium separates opposing surfaces of the first conductive plate and the second conductive plate; the outer housing having a bottom portion forming a second cavity, the second cavity including means for measuring an electromagnetic characteristic of a capacitor formed by the first conductive plate, the second conductive plate, and the variable-permittivity medium.