A sliding window assembly for a vehicle includes a fixed panel and a sliding panel moveable relative to the fixed panel between an open position and a closed position. An elongated member is connected to the fixed panel and defines a channel extending along a longitudinal axis from a first end to a second end. The channel receives the sliding panel for movement of the sliding panel relative to the fixed panel. A rail is disposed in the channel along the longitudinal axis and is spaced along the longitudinal axis from the first end. The elongated member defines a drain hole molded into the elongated member in the channel. The drain hole is defined between the rail and the first end of the channel along the axis for draining water from the channel.