A sprinkler apparatus 10 for providing more even coverage of a sprinkled area with water which is achieved by a different speed of rotation of a water deflector 13 relative to a water diffuser 12 in a wobbling sprinkler head. A diffuser head 11 is rotatably attached to a base 16 and has a water diffuser 12 for diffusing water passing therethrough. A water deflector 13 is rotatably attached to the rotatable diffuser head 11 for directing water emitting from the nozzle 21 through the water diffuser 12. A viscous fluid brake 15 couples the water deflector 13 to the water diffuser 12 to vary the speed of rotation of the water diffuser 12 relative to the water deflector 13 to obtain a more even coverage of the area being sprinkled.