Another MAJOR problem is the fallibility of human memory. Often I will hear people say, "This is the hottest (or coldest) I can ever remember," but looking at official records, it has been hotter or colder many times. People just forget. How many people realize the hottest period in American history was the mid 1930s, during the Dust Bowl era? Temps then were MUCH higher than today.
I just took a quick glance through the detailed daily weather data I've been keeping during hunting season since 1987. I found all sorts of late hot periods around this time of year into MZ season. The high temp was 84 degrees on Oct. 27 in 1989. 80 degrees on Nov. 8, 1999. 81 on Oct. 28, 2000. 82 on Nov. 3, 2003. 81 on Nov. 15, 2009, etc. I even found 78 degrees on Thanksgiving, 1999.