I'll bet you're not following AlGores Global Warming Rules For Thermometer Placement, are you?
Remember....after Jan 1 2008, all outdoor thermometers now are to be placed within 7.5 feet or less of an air conditioner unit. If one is not available, several mirrors may be placed around the base of the temperature recording unit.
Check the thread again, we have the charts now, you can see what we are talking about.