We all recognize that the natural world is highly dynamic and that the variability in the natural environment can have a profound effect on system performance. When and how do we have to incorporate the dynamics of the atmosphere and ocean into training scenarios? When can we use archival data and when must we replicate the environmental variability that currently exists - variability which participating live systems actually perceive? We discuss current research in generating, delivering and interpreting dynamic synthetic environments and how that can be introduced into constructive, live and virtual exercises. Particular attention is paid to experience in providing METOC (meteorological and oceanographic) data to Fleet Battle Experiments and Global War Games. We conclude with a rationale for linking environmental data delivered to simulations with environmental data used for operational, tactical decision support. While much of the technical work is being reported through the SIW conferences, the focus of this paper is on a broad scope of exercises and novel ways to achieve more comprehensive, realistic training at reasonable cost.