We studied the seasonal variability of the water circulation in the Caspian Sea with the use of an improved model of the thermohydrodynamical processes. In comparison with recent studies , in the model proposed, the problem is solved over a finer spatial grid using 6-h atmospheric conditions. The explicit description of the mesoscale processes and high-frequency oscillations with time scales of similar to10(2) - 10(4) s allowed us to widen the set of phenomena represented by the model. We analyzed the monthly mean characteristics of the water circulation, the eddy generation in the jet alongshore currents, the three-dimensional structure of the upwelling, the currents off the Kura River, and the currents along the eastern coast of the sea. The results of the modeling are compared with the data of field observations of the large-scale and mesoscale phenomena in the Caspian Sea. The subsurface cyclonic currents (below 20-50 m) in the deep-water parts of the sea are the most stable during a year. The seasonal variability of the surface currents is caused by the wind variability and momentum exchange with the subsurface currents.