Lake Winnipeg is a large (23,000 km2), shallow (12 m), homogeneous lake composed of two well defined basins separated by a central area of irregular geometry that includes the Narrows. Lake current was measured at 3 depths from two moorings in the Narrows and was compared with water level records from 7 gauges around the lake throughout the ice free season (May 15--October 15, 1976). The dominant lake response was a forced response produced by natural fluctuations in the wind with periods of 50--100 hours. Large amplitude water level and current fluctuations were produced by low wind speeds due to resonance caused by wind periodicity near the 39 hour natural cobasin oscillation of the lake. Although damping is subcritical, allowing for a resonant response, Lake Winnipeg is heavily damped compared to deep lakes. The cobasin oscillation is so low in frequency that a classical wind setup is unlikely to occur. Free oscillations were of secondary importance to the large scale dynamics of the lake. Several whole lake modes higher than the first were identified from the current and water level records but the amplitudes of these modes were very small compared to the free response of the Great Lakes. There was also a detectable response in the records at several natural frequencies of the individual basins and at the M2 tide.