Variability of model dust emissions by wind erosion was tested for sensitivity to variations of wind speed in the United States for a 31-year period (1948--1978) and for a wide range of threshold velocities that arise from differing precipitation scenarios, from drought to abundant rainfall. Results shows that dust production increased about an order of magnitude when threshold velocities were changed from those appropriate for abundant rainfall to those appropriate for drought. About the same range of variability for dust production was seen in the model results when soil conditions and land use were held constant and U.S. wind data for 1948--1978 were used. Maximum dust production for the United States occurs in the spring, and minimum dust production occurs in the summer. Maximum model dust production for a 1-year period occurred in the early 1950's and early 1970's, when a U.S. wind record for 1948--1978 was used. The location of maximum dust production is the area including the panhandles of Texas and Oklahoma and some surrounding areas. ¿ American Geophysical Union 1989