Why doesn’t the Chicago National Weather Service take the average of the high and low temperatures of Midway, O’Hare and the lakefront and consider it the official Chicago temperature for a given day? Wouldn’t that eliminate some of the biases reported at a given location?
Alexander Zazi, Chicago
By definition, an average temperature at a given location is exactly that: the average temperature at that spot. Temperatures at any given moment vary, sometimes significantly, across a geographical area as large as Chicago. Averaging temperatures at several locations to create a new “average” would destroy the characteristics of each of the individual locations (characteristics that you have referred to as “biases”). This might seem desirable, but the question then becomes: What locations should be selected in determining the new average?