On my ,12 OUtlander GT (3.0 6 sp auto, 5000 mi) since the cold has finally arrived, it seem as though the fuel mileage has really taken a dive.

Going by the on-board computer, I've lost 4 MPG average. My daily commute used to be in the 22 mpg range and now it's down the the 18 range.

Anybody else notice a drop when it's cold?

 

Hi, You will always get this due to the oil being a bit thicker in the cold until the engine warms up..

Gazza

 

I got worse gas mileage as well since the weather dipped into 30s. but only 1-3 mpg depending on the length of the drive.

The best gas mileage has been when it was around 70s and no A/C running.

It does have 10 qts of ATF and over 10 qts of coolant, so I guess it takes longer to warm up these fluids in colder weather.

Also colder air is denser and will create more drag therefore requiring more gas to maintain speed.

 

I have also found that if you use snow tires your mileage drops a lot as well.

 

That is usually a relatively negligible amount because the drag is almost entirely cancelled out by the increased mileage from that same dense air going into the engine.

 

I idle more in the winter cleaning the car off and warming it up a bit before the wife gets in. Fall/spring you don't have to do this as much. Summer I have to blast the A/C to cool the cabin down.
Winter uses the A/C compressor too for the defrost.

Attached my mileage in the Toronto area. I plotted average temperature (C) with my L/100km measurements.

 

Gas mileage will always be worse in the winter. The main causes (some already mentioned) are:
1. Winter blended fuel. Refineries can put more (cheaper) butane in the gasoline because the EPA allows them to use a higher vapor pressure formula. This lowers the BTU's, and in effect mpg. FYI, this cost is generally passed on and winter gas is BTU for BTU usually cheaper than summer gas.
2. Cold weather keeps the engine in "choke" mode (rich mixture, high RPMs) much longer. You only get half the mpg for the first 2-3 miles of every trip.
3. Cold fluids. Not only the oil, but transmission and power steering put a much heavier load on the engine until things warm up.
4. More HP. The cold dense air coupled with the higher octane of the winter blended fuel (more butane) boosts a modern engine's maximum fuel flow rate and horsepower considerably. Unfortunately A 5%-10% horsepower boost is most easily felt in the wallet.
5. Snow tires, if you use them, have much higher rolling resistance.
6. Most people idle (warm up) a lot more in the winter than in the summer.

Other factors to keep in mind are that I use AWD much more in the winter than in the summer. I also have to run the defroster, which by default runs the AC on the Outlander, on almost every trip.

I get about 10-15% worse mpg between Halloween and Easter than I do the rest of the year in all of my vehicles.

 

You can turn off AC after you turn on the defroster, unfortunately you have to turn off the AC every time you go from any other blower setting to the defroster.

 

Even if you turn the little snowflake off, you can still hear the defroster kick the compressor on and off.

 

It doesn't do that on mine. Perhaps its an auto A/C only feature?