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 2014. In October 2014, new features were added to the "current month" product and the "current day" product was phased out. A copy of last month's 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".