A method was suggested and demonstrated for predicting the field performance of sprinklers operated in unsteady wind conditions from a limited number of single sprinkler tests and a limited amount of wind data. The usefulness of a single sprinkler test is increased by rotating it to any angle, thus enabling it to depict the effects of wind from any direction and resulting in a reduction of the number of tests needed. Wind data is grouped into 45 angle segments and averaged within five mile per hour wind speed intervals. The method involves synthesizing the effects of unsteady wind on sprinkler water distribution by utilizing a computer to stack a series of sprinkler tests conducted in steady wind. The resulting total stacked test pattern representing the influence of unsteady wind is utilized for predicting the uniformity of water distribution for a sprinkler operated in the wind conditions modeled.