A third-generation wave model was applied to the Gulf of California to hindcast wave spectra and to assess model sensitivity to wind variability on the basis of three different numerical simulations: (1) when a synthetic wind field of varying randomness is adopted and when the forcing wind field considered has an input time step of (2) 6 hours and (3) 5 min. In the first idealized simulation the wave field induced by a constant wind field is compared with the result when white noise was added to the originally constant forcing winds. Results from these numerical simulations demonstrate that wave energy increases with wind variability, even though the mean wind is kept constant. In the second and third simulations the forcing wind is averaged for periods of 6 hours and 5 min, which represent relatively low and high timescale variability, respectively. These realistic wind fields were constructed as a blend of detailed in situ measurements and analysis information, representing wind variability in both speed and direction. The results show that high-variability winds induce broad directional wave spectra and secondary peaks with similar magnitude as the main peak (bimodal spectra). With the presence of wind gustiness and a continuous spectrum of wind variability, all source terms are expected to play a significant role in the evolution of the wave spectrum. ¿ 1998 American Geophysical Union