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.
The "current month" link has this month and previous months back to January 2014 (use tabs at the bottom of the page to see other months). Seasonal snowfall and heating degree day columns were added to the tab called "Annual 2014".
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".