Cars using summer-blend gasoline spew fewer harmful emissions and get slightly better fuel economy than those using winter-blend gas during the summer months.

The difference between conventional summer- and winter-blend gasoline has to do with the Reid Vapor Pressure of the fuel. RVP relates to the volatility of a gasoline. The more volatile a gasoline, the more likely it will evaporate as the temperatures rises; evaporated gasoline contributes to unhealthy ozone and smog levels. Summer gasoline has a low RVP and is less likely to evaporate when compared to the high RVP winter grade. The Environmental Protection Agency says conventional summer-blend gasoline contains 1.7 percent more energy than winter-blend gas, which contributes to the summer blend’s slightly better gas mileage.

The Energy Information Administration says the switch between the two fuels happens twice a year, once in the fall (winter blend) and again in the spring (summer blend). Summer-blend gasoline is typically more expensive to produce than the winter blend, and it won’t affect vehicle performance or the durability of the engine and fuel system, according to the EPA.

In many large cities as well as California and New England, the EPA requires the use of reformulated summer- and winter-blend gasolines. These RFGs contain oxygenates that lower RVP and other toxic chemicals even further than conventional gasoline.

 

I thought that was interesting. I never knew there was a physical difference in gas between summer and winter

 

That is interesting. I always thought my gas mileage sucked more because I let the truck idle for about 10 minutes before i get in...lol... Damn auto starter..lol..

 

I thought it was all the extra weight I put in the bed for better traction.

 

Yeah, winter blend always gets less mileage but is also SUPPOSED to be cheaper. I got gas last night and 93 oct was 3.24/gal here......ouch!!

 

Gas also evaporates faster in cold temps.

 

Ouch? You want ouch? THe gas you got last night is $0.85/litre. That's for 93 oct, right? I got gas yesterday, and it was $1.07/lire...for 89 oct!! That's $4.06/gal!!! I wish I had your prices!

 

True but my MPG is about 9-10. IDK what yours is but in the end it might still cost me more.....

 

Supply and Demand, my friend. During the winter time there are more people heating their houses with oil and therefore raising the price of the product to help meet the demand.

If everyone would stop heating their homes maybe the winter blend would end up actually being cheaper!

 

Yeah, I'm getting about the same...the cold weather doesn't help either!