Unpleasantly Warm, Muggy Weather and My Running

I am quite beside myself with the state of the "winter" weather here in northern Florida.  Every day it's muggy and warm, not exactly conducive to the type of long, pleasant runs I had been anticipating for now.  Instead, I am left with the choice of building up my mileage by combining two separate runs: one in the morning pounding the streets of my neighborhood and then one late night after work, in my 24-hour workout gym on a treadmill.  Together I have been putting up impressive numbers (for myself) and am on pace to surpass last month's total.  Still, I would gladly trade that second treadmill run for a longer morning run in the cool, dry January air that used to exist in a bygone age.  Apparently it does not anymore, and from what I have seen on weather reports, no relief is in sight.