Google me this:
1. I'm looking for an annual average temperature graph like this one , for Chicago, or anywhere in the Midwest other than St. Louis, MO. To be clear, a simple mean temperature record by year, from, say 1900 to the present day. NOT variability in mean, maximum and minimum, NOT deviation from the mean, NOT skewness statistics (whatever that is). Just a graph of the average temperature for the last 100 years, give or take a decade.
2. Remember when the weather reports included historical data? 'This is the coldest day in Chicago since this date in 1944 . . .' Try to find that data. (Now, are there a lot of 404 errors in there, or is it me? )
While I was looking, I did find others asking similar questions. Also found a great slide show of weather data thermometers' toasty-warm locations (black tar roof, asphalt parking lot, etc.) at Surfacestations.org, where they are trying to assess weather data collection sites. They're looking for help in Illinois, to find and photograph problem data collection locations. (Their blog is Watts Up With That?)
But no luck on the temperature graphs, or the date-specific comparative temperature data. So if you find a source, please let me know.