73.4 miles / 63.6 mpg

Well, now that the climate out here in Phoenix is in the 80's, I've noticed a big difference in mpg's. In the summer time when temps are 100+, I typically averaged 50 mpg on a daily basis. I still use my AC all the time, but my mpg's have gotten significantly better. I've now been averaging upper 50's / low 60's. Today I drove 73.4 miles and got 63.6 mpg. All in "normal mode." I guess temps can have a big difference on mpg's! Has anyone else noticed this?

From what I have read, temps do make a difference. A lot of us are going to see a drop in MPG as it gets colder. I have already seen a 54MPG go down to 51.5MPG. And it has been in the 30s and 40s where I live.

Yes and the effect appears to peak at ~80F in North Alabama. Any warmer and A/C is necessary. Any cooler and air density as well was warm-up effects begin to predominate.

Bob Wilson

It has been in the low forties here in the morning and late evening. At the same times I'm going to and coming home from work and it is killing my gas mileage. The warm up times are increasing by two or three minutes each way. And when your only driving three miles each way it is not helping at all.

Ditto Eaglesight333's experience. For the past 800+ miles, I've avg'd 54mpg, this week - cool (40-50) and rainy and I've dropped almost 3 mpg avg. In all my other cars, including the '69 Vette with the stroker motor I sold last year, I always got better mileage in cooler weather, and then, the big drop when it fell below freezing, so, I'm puzzled. Guess the inj. mapping must be real different on the Prius, even though the car is in a heated (60) garage.

i've noticed the difference seems to be A/C vs. No A/C. our car has gone from 52 mpg to 57 mpg just because we are not using the A/C.

same gas, same route, same habits, etc.

Mileage is up here in Mississippi, I feel I am using less A/C at 70 than I was at 95. Mind you, when it rains, mileage is down.