NPS Greater Yellowstone Network Climate Monitoring

The NPS Greater Yellowstone Inventory and Monitoring Network (GRYN) represents Bighorn Canyon National Recreation Area, Grand Teton National Park, and Yellowstone National Park. Climate status and trend reporting for these parks includes key climate parameters such as temperature, precipitation, and stream flow.

Determining how climate within and around GRYN parks varies at different spatial and temporal scales, and how  climate in and around parks changes relative to the near and long term past helps NPS managers evaluate the health of many crucial resources.

The GRYN compiles, inteprets, and reports data from approximately thirty-two weather stations and stream gages located within and adjacent to GRYN parks. Measurements taken from any single weather station are influenced by many factors, including elevation, slope, aspect, and the interactions between air currents and topographic features. For this reason, patterns observed at two weather stations in the same general area may differ significantly. Reporting on climate for an entire region must account for important local and zonal differences.

The GRYN has proposed climate zones within the GYA based on long-term temperature and precipitation patterns: northern and southern Yellowstone, eastern and western Grand Teton National Park, and the Bighorn Canyon National Recreation Area. Northern Yellowstone is warmer and drier than southern Yellowstone and receives most of its precipitation in the summer. In contrast, southern Yellowstone and the Tetons receive most of their precipitation in the winter, with the western slope of the Tetons receiving significantly more snow from air currents that carry moisture from the Pacific Northwest. Bighorn Canyon is the warmest and driest zone, with peak precipitation during April, May, and June.

Annual climate reports summarize data for each climate zone and/or park. Average temperature, precipitation, snow depth, and snow density (snow water equivalent) are presented in comparison to thirty-year averages for these parameters.

Climate trend reports are planned at 5-7 year intervals to provide substantial synthesis of climate data and discuss known and potential influences on park resources.

Data used for climate reporting come from a variety of sources, including  the National Oceanic and Atmospheric Administration (NOAA), the Natural Resource Conservation Service, and the US Geological Survey.