A variable arc sprinkler may be set to numerous positions along a continuum to adjust the arcuate span of the sprinkler. The sprinkler includes a nozzle body and a valve sleeve that helically engage each other to define an arcuate slot that may be adjusted at the top of the sprinkler to a desired arcuate span. The sprinkler may include a flow rate adjustment device that may be adjusted by actuation or rotation of an outer wall portion of the sprinkler. Rotation of the outer wall portion may cause a throttle control member to move axially to or away from an inlet, or may cause one or more restrictor elements to open or close, to control the flow rate of the sprinkler.