There were 3 years of summer-like Thanksgiving weekends. It's supposed to be cool on Thanksgiving, so that cooking a big meal warms the house! Now that everyone goes out and has climate control, that social convention has been buried.
If we go back 5 years, the Thanksgiving weekends often had skiffs of snow. People used to come out though, to enjoy nature. It is always past colours peak in this area, so the lure was just the fresh air, sunshine, and being out of the city.
Yup, things change. Change IS the only constant.