Sorry if this has been addressed elsewhere, but I can't find it. I seem to get better gas mileage during the day than at night. I've noticed this on three separate trips. On each one I drove about 100 miles at night, averaged about 52 MPG. Return trip during the day, averaged about 58 MPG. I realize the outside temperature has something to do with it, but does 4-8 degrees Fahrenheit really make that big of an impact? On each occasion my day temperature was in the low to mid 70s and night temperature in the high 60s.
That can happen. I get better mileage going from work (during the night) than going to work (during the day). One big reason is that work is at a higher elevation. That and there's more stop and go driving on the way home too.
Would love to give you exact elevations, but wikipedia is down. On 1 trip yes - Richmond to Roanoke is an uphill drive On the other 2, no not much - Richmond to Fairfax All points are in Virginia
I'd bet the temperature difference is a lot bigger under the hood of a car resting in sunlight and after dark.
FYI... I commute from Fredericksburg to Springfield every day. Since the time change, and cooler weather, my avergae tank went from 54 MPG to 50.5 MPG. There are two reasons, so I think: 1) I now have to drive with the lights on on my return trip (and that takes more gas to recharge the battery) and 2) the temperaure has dropped.
My guess is that the colder night air is denser and thus creates more wind resistance. Ever notice how drag racers go faster at Denver then at sea level? Colder air also allows for more horsepower (not a big concern with the Prius).
I have to say now that it is dark in the morning I am not doing as well. I do not think it is temperature, because my homeward commute is generally at the high of the day, such as it is. I think that when it is dark out it is harder to drive, you are concentrating more on the road and less on the MFD, and pulse and guide. I hope that it can become more automatic, but I am somewhat new to the pulse and guide thing because of two numb feet from back surgery. I am getting better and better but it is not automatic, I need the visual feedback from the MFD. When I need to mind the road in the dark the MFD goes out the window. Oh Well. I will keep practicing.
