A method for measuring a particles' precipitation rate includes the steps of acquiring at least one first image during a precipitation event through an image acquisition device having a sensor and lens; detecting the particles of the precipitation in the at least one first image by subtracting a background of the first image and setting a brightness threshold for detecting the particles, the particles being visible as a plurality of streaks in the image, wherein a first portion of the plurality of streaks comprises blurred streaks, and a second portion of the plurality of streaks comprises focused streaks; determining an apparent diameter and an apparent length for the plurality of streaks; estimating an actual diameter and an actual length for the plurality of streaks by resolving an equations' system having three equations and three unknowns, namely the actual diameter, the actual length and a depth position of the plurality of streaks, the depth position being the position of each particle from the lens, in which a first equation has the actual diameter as unknown in function of the depth position, a second equation has the actual length as unknown in function of the depth position and a third equation equals the theoretical terminal velocity of the particles with an estimated velocity of the particles in function of the depth position; estimating the velocity of the particles based on the ratio between a net streak length and an exposure time used to take at least one first image; estimating the particles' precipitation rate based on the actual diameter and the velocity (v).