[stevio]

I get less mpgs in the winter than in summer.

[teeman8r]

that is the winter blends fault.

[gbs]

Ethanol

[Tallguy]

I get less mpgs in the winter than in summer.

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So do I, but warming your car up while scraping ice and (possibly) under inflated tires due to prevailing temperatures explain a lot of it. Winter blend gas?

[ThunderSleeps]

I get less mpgs in the winter than in summer.

I've noticed that too. I attribute it to two, maybe three or four things.

First and foremost there are winter additives put in the fuel. These slightly reduce the chemical energy per gallon.

Second, in winter time I tend to run the car sitting still to warm it up, often while I'm out scraping snow/ice off the windows. That's fuel burned for no miles driven.

Third, (kind of iffy) in winter I run the heat. That means the fan is drawing power. Summers are typically mild enough I don't run AC much. I don't even roll the windows down all the way, I've found a way to roll two windows down just an inch or two that provides a nice breeze.

Four, (also kind of iffy) in winter days are shorter, so I'm more likely to be driving with headlights on. They are a decent draw of electrical current. All that energy comes out of the gas tank.