An attempt is made to develop an objective method of forecasting summer precipitation at Salt Lake City, using moisture variables on a scatter diagram. These variables are surface dew point at Salt Lake City vs. the minimum temperature-dew-point spread between 700 and 500 mb. at a nearby raob station selected according to the 12,000-foot wind direction at Salt Lake City. Probability lines for the occurrence of both measurable rain and a trace or more are drawn. Skill scores and percentage of correct forecasts are computed for both original and test data and compared with Weather Bureau staff forecasts.