The seismic 'background noise' detected by the seismometer on the Viking lander 2 has an extremely high correlation with the measured wind speed at the landing site. When displayed in a compressed form, the nearly continuous seismic data clearly exhibit the diurnal as well as seasonal variations of the Martian wind activity. A preliminary spectral analysis of the long-term variation of the background noise indicates persistent spectral peaks at periods near 1.5, 3, 7 and 10--20 sols for the first 560 sols (0.84 Martian year) of observation.