I was coming back from Las Vegas against VERY STRONG headwinds, in the neighborhood of 50mph across the desert, Edwards AFB, Tehachipi Pass, etc. and about 30mph winds up the central valley, all the while driving at 75 or so. Still, I got 38+

This was calculated, the dash thing read 36.1 mpg (I always calculate it, as the gauge is always low, usually 1-2 mpg, once 8 mpg low (went 565 miles on a tank, which is impossible at the 43 mpg the readout said, but it calculated out to a little over 51 mpg)