My favorate is when you get your registration license plate sticker each year for the car, they want you to give them the milage on the odometer. One year when I was driving a Ford Explorer, the odometer was at 123456. They guy at the MOV didn't believe me and said that he had to verify it, so I showed him. Fluke luck it was at that number, but it still sticks in my memory.
I just concluded a 200 mile trip down interstate 70. Had a brisk headwind of 20mph. Kept the speedometer between 70 and 80 the whole way. Average 38.3 mpg's. Not good but in 3 hours I will do the reverse trip and see if I can get back to mid 40s. Current temperature is 32 degrees.
Generally wind dies down at night, so your trip back may not feature much of a tailwind. But getting 38 mpg at a windspeed of 100 mph in a car shaped like the Niro is pretty darned good! Especially if you have the 18" wheels. Bet it is the best you have ever done in any car under such conditions.