Obtaining Precipitation Data from PRISM

PRISM data (Parameter-elevation Regressions on Independent Slopes Model) provides maps of each state with its average annual precipitation.  You may purchase precipitation maps in addition to downloading them.

Go to the USDA PRISM web site at www.wcc.nrcs.usda.gov/water/climate/prism/prism.html.  If you have trouble with this link, follow the bulletted steps below:

• Go to the NRCS homage at http://www.nrcs.usda.gov,
• Click on the Technical Resources button at the page top,
• Scroll down and click on the Water Resources link,
• Choose the Water and Climate Data link,
• Click the Climate link,
• Choose the Spatial Climate Products (PRISM) link.

1. Choose the Cartographic-Quality Maps link.  Note that there are also a link for Gridded Precipitation Maps. The first link gives average annual precipitation for the different US states.
2. Choose Maps near the top of the screen.
3. Choose a state by its two-letter abbreviation.
4. You will see a small thumbnail image of the state's precipitation map.  If you are going to print the map to a large format plotter, choose the Map ps link (post script files are very large (e.g., 32 MB for Texas) but can also be read by typical graphics programs such as Paintshop Pro.  Otherwise, a color Adobe Acrobat (.pdf) map of the state can be downloaded or viewed by clicking the Map pdf link.

1. Backtrack to the main PRISM website at www.wcc.nrcs.usda.gov/water/climate/prism/prism.html.
2. Again choose the Cartographic-Quality Maps link.
3. Click on Data near the top of the screen.  Precipitation data for different areas (i.e., states, regions, country) are available.
4. For example, click on the State link.
5. Scroll down until you find the state you need data for.
6. Each state offers its data in ARC/INFO, ArcView, and ASCII formats - click the appropriate link.  The ArcView precipitation data for Utah is shown below.