Hodographs of resultant surface winds are presented for each hour of the day for July and August at stations in the Columbia Basin of eastern Washington and Oregon. Marked diurnal wind variations occur at all stations, and most are related to local topography. The end point of the resultant wind vector usually turns clockwise, although at some stations it shows a tendency to turn counterclockwise during part of the day. Departures of resultant winds at individual hours from the average of all 24 resultant winds at the station show flow out of the basin during the day and inflow at night. A phase difference occurs between the western and eastern slopes of the basin. This difference appears related to inland progression from western Washington of a large-scale sea-breeze circulation.