I've owned my Prime for about two weeks now and during that time I've driven around 1,500 miles. Last week, when the weather was warmer, I was able to go about 32 miles in full electric mode. For the past two days, when the weather has been cooler (in the high 30s to low 40s) I've only been able to eek out about 25 miles in full electric mode. I'm certainly not complaining since my commute each way is about 70 miles. On the way in to work with a full charge, when the weather was warmer, I was averaging abut 135 MPG combined. This week, in the cooler weather, I've only averaged about 115 MPG. On the way home, without any charge, I've been averaging about 68 MPG regardless of the temperature. I guess cold definitely effects the distance one can travel on electric only. Nonetheless, the MPG is outstanding either way. Interesting!