Deadline To Complete Summer Blend Gas Switch June 1

By Jessica Waters, WNEG Radio

Summer may not officially start until June 21, but the deadline for the annual switch to “summer blend” gas is June 1.

Under EPA guidelines, gas refineries are required to switch from production of “winter blend” gasoline to “summer blends” no later than May 1. Retailers are given until June 1 to complete the switchover.

The switch to gasoline manufactured for warmer weather can contribute to higher prices at the fuel pump. Increased demand due to the start of summer vacation travel also plays a role in the price increases, according to AAA. 

From May 1 to Sept. 15, regulations put in place by the Environmental Protection Agency require the sale of gasoline that does not include certain less-expensive, but more volatile chemicals, including butane.

AAA explains, “The difference in summer blend gasoline involves the fuel’s Reid Vapor Pressure (RVP), which is a measure of how easily the fuel evaporates at a given temperature. Winter-blend gas has a higher RVP because the fuel must be able to evaporate at low temperatures for the engine to operate properly. Summer-blend gas has a lower RVP to prevent excessive evaporation when outside temperatures rise. That evaporation can cause vapor lock in an engine on hot days and contributes to unhealthy ground-level ozone and smog levels.”

According to the U.S. Energy Information Administration (EIA), summer-blend gas contains 2 percent butane, but that percentage is higher in the winter blend. Butane, which is more readily known as a lighter fluid and fuel canisters used for gas grills and camping, is also a component of winter blend gasoline, as it is less expensive than other gasoline components, but its high volatility limits how much can be included in summer-grade fuel.

While the switch to summer blend gasoline can increase the price-per-gallon, the increased fuel efficiency will help offset that cost, according to EIA.

A AAA data sheet explains, “Even though prices are slightly higher for summer blend fuel—because it contains less butane—the summer blend contains 1.7 percent more energy than the winter blend. As a result, your gas mileage should be a little higher in the summer months to offset some of the added cost you pay at the pump.

Additionally, engines warm up to an efficient temperature faster than in the cold weather of winter, and warm air causes less aerodynamic drag than cold air, both of which can contribute to better fuel; economy during the summer months. However, driving with the car windows open, or using the car’s air conditioner, can reduce the vehicle’s fuel efficiency.

Other ways to increase your car’s fuel efficiency include keeping your tires properly inflated, avoiding rapid acceleration and braking, and using cruise control on the highway, AAA advises.