This study advances theory articulating the micro-level processes behind public organization adaptation to extreme weather. It tackles a persistent puzzle about the limited adaptation to extreme weather among public organizations: why does adaptation remain deficit after public organizations have experienced repeated extreme weather and some catastrophic consequences? We develop a computational agent-based model that integrates extant theory and data from semi-structured interviews of U.S. public transit agency managers, and use the model to investigate how micro-level cognition and behavior interact with environmental constraints to facilitate or impede the diffusion of adaptation. We articulate in greater detail how experience with influential extreme weather events matters to adaptation, highlighting that such experience is insufficient for adaptation to occur. A key insight is that the potential benefits from both increased risk perception and additional financial resources stemming from disaster- or non-disaster-induced opportunities can be underutilized, absent effective coupling between heightened risk perception and availability of resources that creates windows for adaptation. Using this insight, we further identify managerial and policy interventions with maximum leverage to promote adaptation to extreme weather in public organizations. The experiments show that slowing risk perception decay and synchronizing opportunities with extreme weather occurrences can stimulate adaptation.