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Map Layer Info

United States Average Annual Precipitation, 1961-1990

What this map layer shows:

Average annual precipitation for the conterminous United States from 1961 through 1990.
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Background Information
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The Natural Resources Conservation Service (NRCS) supports the development and transfer of climate information and technology for natural resources conservation as part of its mission. The average annual precipitation data for this map layer were produced through a partnership between the NRCS and the Spatial Climate Analysis Service at Oregon State University (OSU). NRCS provided oversight and funding to OSU for the PRISM Climate Mapping Project. PRISM is a unique modeling system designed to mimic the decision-making process an expert climatologist would use when creating a climate map.

This map layer shows polygons of average annual precipitation for the conterminous United States from 1961 through 1990. PRISM-derived raster data form the underlying data set from which the polygons and vectors were created. Each polygon represents an area with a constant value for the average annual precipitation, as determined by the PRISM model. More detailed information on the PRISM project is available at the NRCS PRISM Climate Mapping Project and PRISM Overview pages.