When do gas stations switch to summer blend

Refiners are currently switching to make summer-grade gasoline ahead of the May 1 compliance date for refiners and product terminals. Summer-grade gasoline has a lower volatility than winter-grade gasoline to limit evaporative emissions that normally increase with warm weather and cause unhealthy ground-level ozone. Volatility is a measure of how easily a liquid or solid will change into a vapor. The higher the RVP, the more volatile the gasoline.

While the Environmental Protection Agency EPA requires lower-volatility summer gasoline, aside from any government regulation, gasoline's RVP must be limited to ensure that the fuel does not vaporize in the fuel system. They can then switch back in September. You need to keep in mind that winter gas is not good for your car or the environment during the summer, so avoid using gas from last season in your car now.

And be sure to always pay attention to the quality of products you buy for your car. If you have any questions about the best products for your vehicle, come to Gold Eagle for assistance with your decision. I wonder why when using the winter blend in the summer, my gas mileage is higher than when I use a summer blend. Therefore, gas stations can often sell their gas at a lower price in the winter vs. Gas stations must switch fuels based on the season in order to comply with regulations directed by the Environmental Protection Agency EPA.

According to the EPA , they regulate the vapor pressure of gasoline sold at retail stations during the summer ozone season June 1 to September 15 to reduce evaporative emissions from gasoline that contribute to ground-level ozone and diminish the effects of ozone-related health problems.

That means using higher concentrations of pricier additives, such as alkylates and reformates, and sometimes a lengthier refining process that slightly reduces yields. All of that—and processing those 14 special blends—helps drive up pump prices during the summer. Some states specify multiple summer blends. This is why gas prices can vary widely across counties within just one state. Despite those higher prices, summer gasoline contains about 1. Winter gasoline varies widely in volatility throughout the season.

Refiners constantly adjust their RVP to as high as 15 psi—higher than sea-level atmospheric pressure, which is The vapor pressure varies by month, region, and octane. In frigid temperatures, higher-volatility fuel is essential and does not cause the smog effect it would in the summer.