July and South Carolina and I don't use A/C (not in my car)

 

harrumph! with the window shade installed and window cracked a bit - and as I get into the car I find the steering wheel too hot to hold...I lower the windows and keep my face near the window 'cause of that "oven" feeling, oh, yeah! Auto climate zone and set it on 82 degrees. air conditioning on some days is real good in Columbia!

Yep - going to try midgrade next fillup too.

 

I tried using the mid grade and actually had to fight to keep the mileage up. I think some of the differences people are seeing might be based on what is in their regular gasoline. For example when I was out at hybridfest in Wisconsin, I could only find non-ethanol gas in their premium brand gasolines close to the hotel and wound up with a tank of that, which gave me a little better than the mid grade & regular but it has also been warmer. I go back to my regular fuel next week and will see if it drops off any but I really don't expect it to.