Difficulty of deciding on control action depends on the weather and traffic conditions. Weather signature on different days can categorize days into days with little decision difficulty, days with moderate decision difficulty and days with high decision difficulty. This paper examines performance of different data mining methods in the three regions of decision difficulty. Not surprisingly, data mining methods have the best performance in the region of little decision difficulty and have the poorest performance in the region of most decision difficulty. In applications where data mining methods have differing performance in differing regions, it would be more useful to characterize the region specific performance instead of characterizing performance by a single parameter.