Water spray nozzle for a snow gun, of the type comprising a distributor (13), housed between a water-supply lower chamber (10a) and a water-distribution upper chamber (10b) ending in an annular exit (12), said distributor (13) having a cylindrical surface, at least part of which (band l 1 -l 2 ) seals against a corresponding cylindrical area of the wall of the upper chamber (10b), on said cylindrical surface of the distributor a plurality of helical grooves (14) being formed, which grooves receive the water coming from the lower chamber (10a) and lead it into the upper chamber (10b) and towards the annular exit (12) of the nozzle, simultaneously imparting to the same a rotary motion. The ends of said helical grooves (14) in connection with the lower chamber (10a) are formed at axially different heights on the circumference of the distributor (13) and said distributor (13) is axially movable for connecting a different number of said helical grooves (14) with the lower chamber (10a).
