The goal of this work was to classify each ozone episode day in terms of meteorology and ozone characteristics that occurred during the TexAQS 2000 study and the 1993 COAST and to determine the representativeness of each episode day. The episode classes were subjectively determined by reviewing the synoptic scale weather patterns; long-range transport patterns; local circulations patterns including the existence, timing, strength, and extent of land- and sea- breezes; the evolution of planetary boundary layer depth; the magnitude, extent, and location of peak ozone concentrations; and the contribution of aloft regional background ozone concentrations to peak surface ozone concentrations. The findings can be used to aid in the episode selection for modeling and to determine if episodes that are currently being modeled (or ones that are being considered) are representative of common types of ozone episodes; and therefore, are appropriate to be used to help design State Implementation Plans (SIPs).