A system and method to facilitate inventory forecasting of network traffic for a network-based entity are described. In one example, the method includes preprocessing historical data to obtain processed average data, applying modeling and forecasting techniques to the processed average data using a seasonal auto-regressive integrated moving average process to obtain forecasting results, and combining the forecasting results to output combined forecasting data, wherein the combining the forecasting results comprises receiving and storing yearly forecast results. In one implementation, the historical data is normalized by weekly average to obtain normalized data. In another implementation, trend and seasonality are removed from a set of processed data to obtain stationary data. In yet another implementation, yearly forecast results are received and stored.