These observations are taken by the Illinois State Water Survey, located near the corner of Windsor Road and First Street in Champaign using a variety of weather instruments. Real-time conditions at this site are reported here.
For an extended view of precipitation in the Champaign-Urbana area check out the Boneyard Network.
The "current month" link has this month and previous months back to January 2012. I have added a new feature to the spreadsheet called "Annual 2012" used in the "Current Month" product. It is the left-most tab in the spreadsheet. A copy of last months spreadsheet is prepared in pdf format a few days after the end of the month.
The "Daily Summaries by Month" PDF are generated directly from the spreadsheet in "Current Month".