I found this thread, and although it is some years old, it hasn’t closed so I thought I throw in my two cents.
I live just outside of Chicago and the weather here can vary greatly in what is supposed to be Spring or Summer some colder than usual days and we’ve even had 70 degree days in January. So you never know want could happen once you go "kickstand up".
For the record, the coldest I’ve ever ridden was a 200 mile stretch in the low 40’s due to an unexpected temperature drop. My normal minimum cold is about 54F degrees. Now it’s not the cold itself that limits me, I have heated clothing, etc. but rather the likelihood of being run over.
In the Chicagoland area, awareness of motorcyclist only extends from about late March/early April until about late September. Motorist expect and anticipant that there may be motorcycles and bicycles on the road and take due care not to collide with us during this timeframe. However, after September, there is a general misconception that it is too cold for anyone in their right mind to be out riding in/on anything with less than four wheels and they therefore fail to exercise due care. To be honest, I haven’t researched any specific statistics on this, but just from my personal observations, I have seen more vehicle/motorcycle accidents between September and January, than I normally see during the peak riding season. Noting this phenomenon, I make sure to not be riding my motorcycle after Labor Day.