This project was initiated to inventory past and present climate monitoring efforts in the Greater Yellowstone Inventory and Monitoring Network (GRYN). In this report, we provide the following information: • Overview of broad-scale climatic factors and zones important to GRYN park units. • Inventory of weather and climate station locations in and near GRYN park units relevant to the NPS I&M Program. • Results of an inventory of metadata on each weather station, including affiliations for weather-monitoring networks, types of measurements recorded at these stations, and information about the actual measurements (e.g. length of record). • Initial evaluation of the adequacy of coverage for existing weather stations and recommendations for improvements in monitoring weather and climate.