Abstract: A method for determining precipitation rate including on the basis of the signals received on the two polarization channels H and V of the radar, in firstly determining an estimate of the precipitation rates R.sub..alpha. in each range gate i along the radar beam for a single polarization, then a first estimated value (I.sub.1) of the integral of the precipitation rates and, finally, on the basis of the attenuated reflectivity coefficient (Z.sub.H.alpha. (r)), an estimate of the unattenuated differential reflectivity coefficient (Z.sub.DRs (r)). Furthermore, the measured value of the attenuated differential reflectivity coefficient (Z.sub.DRs (r)) is determined, and the integral (I.sub.2) of the precipitation rates is deduced therefrom, then is compared with the first estimated value (I.sub.1) so as to iteratively adjust a parameter (.alpha.) of the method when applied to the polarization H alone. When .alpha.