It was a relocation day, Abilene, KS to Denver, CO. It was very windy, with almost a 90 degree crosswind. I noticed as we were motoring along that our mileage was suffering. We were getting 20 mpg while 25 is normal. I got to thinking and figured that elevation change was also part of the problem. Abilene is 1155 feet and Denver, according to my GPS was 5256. So I did some calculations and found that we consumed about two more gallons than expected. Using some elementary physics I calculated that one gallon of that difference was due to elevation change. The rest had to be due to wind conditions. That's my story and I'm sticking to it.