Abstract: A computer-based Executive Information System (EIS) system for determining the impact of weather and other external and internal factors on the retail industry. Utilizing a multiple regression correlation technique in a predictive model, a correlation of weather variables with store information for specific locations and times is performed to quantify a weather impact model in terms of unit or dollar sales volume change, or any other commercially useful benchmark. The EIS system determines these relationships with location and time specificity. Using the relationship between historical weather and historical sales, the EIS system "deweatherizes" the historical weather to create a normalized historical sales relative to weather based upon normal weather (the 30 year average). This deweatherized data may be used in conjunction with a user-provided managerial plan to produce a revised managerial plan.