Gas Quality and Mileage

[drummer]

I posted this on a completely different forum site and was wondering what the take was here.
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I get about 5 miles less a gallon once the fall comes and it will go back up in spring. Does anyone else see a significant drop in mileage as the fall/winter comes on? This is the third year in a row that I have noticed this for both the bike and the cages. I know they reformulate the gas to produce more heating oil, but is that the reason the mileage goes down?

Thoughts?

 

[darrylri]

Very likely your area switches to oxygenated gas during the winter.

We have it year round in California (and OR and WA), and it definitely cuts 10% off the mileage. In CA's case, the oxygenate is ethanol, but there are other products.

 

[99007]

I have an 04 Rockster with no windshield. I have never noticed much of a difference in gas milage during the winter season here in MI. I get high 30's to low 40's on my day to day commute and two lane travels. Mid 40's on the rare times I do much slabbin.