The purpose of this research study was to empirically study the temporal order of events of postmortem changes in Missoula, Montana utilizing pig (Sus scrofa) cadavers as human proxies by documenting postmortem changes and rate of soft tissue decomposition of three pigs over the course of one year and 19 days. The data from this study will be compared and contrasted to studies that have occurred elsewhere. A full understanding of the postmortem changes and rate of soft tissue decomposition in this area will help forensic anthropologists better understand why the postmortem interval (PMI) may be different in western Montana than in other states or countries. The current research study reveals that previous methods for estimating the PMI using accumulated degree-days (ADD) and total body score (TBS) are not appropriate for Montana, as the climates are too disparate. Building a body of longitudinal data that documents environmentally related soft tissue decomposition or change will be a first step towards developing a decomposition sequence and time scheme that can be used to more accurately estimate the PMI in this region. In Montana a number of partially decomposed cases enter the medico-legal system each year. Thus, greater knowledge about the postmortem period will be a significant contribution to members of the medico-legal community as well as the criminal justice system. In addition, this data could be extended to similar climatic zones.