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."