The Convective Weather Avoidance Model (CWAM) translates gridded, deterministic weather observations and forecasts into Weather Avoidance Fields (WAF). The WAF gives the probability, at each point in the grid, that a pilot will choose to deviate around convective weather at that location. CWAM have been developed and validated for en route, high altitude, level flight, low altitude level flight, and for descending arrivals. A heuristic CWAM for departures was also developed and deployed as part of the Route Availability Planning Tool (RAPT) prototype development in New York and Chicago. This paper presents an evaluation of the departure CWAM that is currently deployed as part of RAPT, based on an analysis of departure traffic in the Chicago terminal area during convective weather events.