Purpose: Grounded in the behavioral ecological model, and to address a lack of park space, this study looked at community members' use of public high school physical activity (PA) facilities during nonschool hours while considering the effects of seasonality. Method: Data included 3,959 observation sweeps across 19 public high school campuses over 1 year (all seasons) in Arizona. Results: Differences in contextual supports were evident between seasons, with facilities being more accessible, usable, and lighted in spring than summer or fall. Accessible facilities were most often outside (68.6% of the time). The highest frequency of sedentary behavior was in summer. Conclusion: The present study expands our understanding about the influence of seasonality as related to community access to PA facilities. During times of extreme temperatures, it may be beneficial to find ways to make indoor PA facilities more accessible to support increased PA levels of community members.