A variable arc sprinkler nozzle is provided for distribution of water through nearly any adjustable arcuate span. The nozzle includes one or more arcuate slots formed by the helical engagement of spiral surfaces of a deflector and a nozzle body. A user may rotate a portion of the nozzle body to select the arcuate span of the one or more slots. A matched precipitation rate feature is adjustable to proportion the amount of water directed to the deflector depending on the extent of the arcuate span. Further, edge fins on the deflector and nozzle body channel water flow at the two edges of the distribution arc to increase the throw radius and to provide fairly uniform water distribution at the edges of the arc.