[torzeck]

Bump.

[bren]

Yes.

[Nahoa]

At least when road conditions are poor I've noticed it seemed true. I've assumed that was based on the inefficiency of poor road conditions including not just snow, but slush, and slick wet surfaces. The mechanical element of that as well as the changes it can force in driving pattern and traffic.

I've wondered if the difference of the colder air is significant enough to affect performance, and if so if that needs to be really dang cold and not just the 20-30 F we experience in this area.

[fiddy yen]

Yes. Due to a couple reasons. Air is more dense when its cold. More air = more fuel. Also engines tend to rev slightly higher for quicker warm ups. Lastly combination of awd system and traction control, winter fuel mileage always goes down.

[SomeRandomer123]

Yes, I always lose 3-5mpg in winter.

[bren]

Originally Posted by fiddy yen

Yes. Due to a couple reasons. Air is more dense when its cold. More air = more fuel. Also engines tend to rev slightly higher for quicker warm ups. Lastly combination of awd system and traction control, winter fuel mileage always goes down.

You missed seasonal fuel formulation differences.

[n55x3]

Originally Posted by bren

You missed seasonal fuel formulation differences.

I've always heard this was the biggest contributor to poor MPG in the winter. Winter blend gas is more volatile (something to do with evaporation points) to help reduce starting problems and I think there may be a diference in the ethenol content but can't remember.

The second biggest factor is engine warm up time. It takes much longer to warm the motor up in sub freezing temps. The engine isn't returning optimal MPG until it reaches normal running temps. If you go for short drives in sub freezing temps you will see very poor MPG. That same drive in 90* weather would likely see a substantial increase in MPG.

Thirdly is driving habits. Many people tend to let their car warm up for a longer period of time before driving off, further more, people like to idle in many situations where they might be inclined to turn the motor off in warmer weather.

[Fryguy29]

Don't forget tires. If you don't monitor your tire pressure, then the pressure will go down during the colder months. This is easily remedied by checking your tire pressure regularly during the winter.

[n55x3]

Originally Posted by Fryguy29

Don't forget tires. If you don't monitor your tire pressure, then the pressure will go down during the colder months. This is easily remedied by checking your tire pressure regularly during the winter.

Yup, that's a good one too!

[02420X3]

Tire pressure is definitely worth checking.

Running the seat and steering wheel warmers and the front and rear defrosters will also contribute to lower mileage.