5 years of commuting data.
Averaged all mpg results at each temperature point.
10 mile commute.
Parked outside, so fully cold-soaked.
Heat off until warmed up (takes most of the trip, so pretty much always off)
No AC in summer.
That slight flattening at 80+F is because of AM/PM temperature differences. Max morning temp is low 80's so anything above that is driving home, 100 ft elevation gain over 10 miles.