Poor Fuel Mileage

I filled up to day, winter blend at 6.21 mpg mid to low 30 degree weather. Actually high temp for Jan. In NW Ohio. I was ecstatic with it for what I was doing. Winter fuel with antigel packages will loose about .5 as standard. It sucks but low temps I have seen high 4's and low 5's at -10. Nothing you can do about it. It balances out in a yearly average. I have seen 8.5 in summer with a spread. Fuel milage takes a hit after 95° too. Not a issue with fuel, but the air temp at that point. 45-60° I see the best opportunity for economy. Dense cool air compresses best. And not running AC.