The present invention relates to a windscreen wiper (1) for a motor vehicle window (3), comprising: a longitudinally extending wiper blade (5), an aerodynamic deflector (9) extending longitudinally above said wiper blade (5), at least one longitudinally extending fluid circulation duct (31, 32) having at least one spraying orifice (35), characterized in that the wiper comprises at least one lower lateral skirt (43, 44) extending longitudinally on a lateral side of the wiper blade (5) and of the spraying orifice (35), the spraying orifice (35) being located between the wiper blade (5) and the lower lateral skirt (43, 44).