A method to delineate climatic regions for the purpose of natural resources management in Idaho is presented. The method is based on the use of geographic information systems (GIS). The objective of this research is to delineate climatic zones, similar to those of the Köppen classification, but applicable to agriculture and other planning purposes. We envision 30 - 40 zones, each a function of temperature, precipitation, solar radiation, actual and potential vegetation, soil type, growing degree days, and date of first and last frost, all of which are a function of location, i.e. topographic variables.
Mean annual precipitation has been digitally mapped by State Climate Services for Idaho at the University of Idaho. A land use and land cover digital data set is acquired from the United States Geological Survey National Geospatial Data Clearinghouse. A soil coverage is obtained from the State Soil Geographic Database, a database developed by the National Cooperative Soil Survey. The Parameter-elevation Regressions on Independent Slopes Model (PRISM) is the source for temperature related data. Digital elevation data for the state are obtained from the United States Geological Survey and are used in the estimation of potential solar radiation on parcels of varying slope and aspect.