GSDA:Obtaining Precipitation Data from the NCDC / NNDC Climate Data Online

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15-minute and hourly precipitation data can be downloaded from the National Climatic Data Center's NNDC Climate Data Online website. The site has data for 6,100 U.S. stations, and some non-U.S. stations.

To download 15-minute or hourly precipitation data

  1. Go to the NNDC Climate Data Online website.
  2. Select "Precipitation Data, 15 minute" (or "Precipitation Data, Hourly") under the Select a dataset section.
  3. Click the Continue button.

    Wait a few moments for the next page to load.

  4. Select the Country option and change its field to "United States".
  5. Click Continue.
  6. Select your desired state under the select a State/Province section.
  7. Choose the option for Selected Station in the state.
  8. Click Continue.
  9. Select the station(s) of choice, noting the period of record for each station.

    You can multi-select stations by holding the Ctrl key when clicking.

  10. Click Continue.
  11. Enter the date criteria and desired output format.

    The space-delimited format works nicely if you want to view the data in your browser.

  12. Click Continue.
  13. Enter a valid email address.
  14. Click the Submit Request button.
  15. Make a note of the URL provided in the ensuing web page.

    When the data request has been processed, the data can be accessed at the URL provided. You will be notified when the data is ready at the email address you entered.

  16. Click on the URL.
  17. Click on the first Access URL, which links to the data file.

We suggest you read the dataset documentation, which is the last access link.

The 15 minute documentation states that all precipitation values are in hundredths of inches (value X 0.01 = inches). You can check the accuracy of the precipitation observation by viewing the entry in the column labeled "UN." If it is HT, then the values are in stored to the tenths place. If it is HI, then the values are stored to the hundredths place.