The basic stage of the modern approach to calculation of a wind wave climate (long-term probability) includes the database formation using numerical hydrodynamic models. The input to such models is atmospheric pressure or wind velocity at some height over sea surface. This information extracted from the reanalysis data. Initially reanalysis intended for research of global processes without description of the extreme phenomena. For this reason, for calculations of a wave climate the reanalysis data have to be corrected. The approach to correction of the reanalysis data and some results are presented. It is shown that for speed of a wind less than 15 m/s the reanalysis as a whole overestimates values in comparison with the measurements, and for speed more than 15 m/s − underestimates. Therefore, for restoration by means of mathematical modelling of a full picture of wave fields including storm situations, it is necessary to apply multistage procedure of correction of the data: separately for each region of the sea and further for storm situations for all sea.