The invention relates to the technical field of automatic window closing, in particular to a window and door rainwater sensor. The window and door rainwater sensor comprises a rainwater collection device and an induction device, wherein the rainwater collection device comprises a rainwater collection cup, a water seepage pipe, a water discharging pipe and a metal block; the bottom of the rainwater collection cup is provided with the water seepage pipe; the water discharging pipe is arranged below the cup rim of the rainwater collection cup; the caliber of the water seepage pipe is smaller than the caliber of the water discharging pipe; a connecting part extends out of the bottom of the rainwater collection cup; the bottom of the connecting part is provided with the metal block. The window and door rainwater sensor disclosed by the invention has the advantages of simple structure and sensitivity in response, an inductive switch can be accurately guided to give an induction signal to a motor during raining so as to close the window and door.