We utilize Classification and Regression Tree analysis to categorize the return of extending the season for upland. High, medium, and low values for cost of water, lint prices, and quality discount/premiums were applied to the lint yield and quality differentials realized from 198 irrigation termination experiments conducted in central Arizona for the crop years of 1991, 1992, 1994, 1996, 1996, 1997, and 2000. The progression of each crop was analyzed using heat units (86/55 F). The relative ranking results of CART, where the most important variable is normalized on 100, were: variety (100), additional heat units after IT-1 (94), yield of IT-1 (93), crop year (83), micronaire associated with IT-1 (68), HUAP for IT-1 (67), lint price (5), water cost (2), and the quality discount/premium year (.09). Significant yield variation from extending the season was found. In addition, agronomic signals for predicting micronaire changes were very important for determining profitability since quality is impacted for both base and any additional yields attained. These are the primary reasons why agronomic factors were found to be more influential than the economic factors considered for explaining the profitability of extending the season for upland.