Many factors are involved in the assessment of "union climate." This concept is often used by firms considering different geographical areas for new facilities and is part of their location analysis. There are a variety of macro-level variables included in the analysis of union climate. Some of the variables presently in use have already been analyzed by researchers in the industrial relations field for their explanatory and predictive abilities relating to unionization. At issue is the overlap in the two bodies of literature, which raises questions concerning the relationship of union climate and the process of unionization: What is union climate? How may it best be conceptualized? and What is its relationship with union activities such as unionization? These possible associations are examined, and the relationship is modeled in a variety of different ways.