Good (mpg) mileage report

Today's high was between 18-22 degrees when I was driving to and from a nordic ski area. Total trip mileage was 55 miles and my scanguage reported 30.7 mpg today while the Ford dash reported a 29.8 mpg average since I fillup the other day. All this on a low E20 blend of fuel. A similar drive during warmer (60 F or above) and no snowcovered roads would likely net a 3-6 mpg improvement. I almost always can exceed the 30 mpg figure running E15-25 blends of fuel.