AAA Texas: Gas prices remain 25 cents higher compared to last year, possible relief coming

SAN ANTONIO (KTSA News) — AAA Texas says the statewide average for a gallon of regular unleaded is coming in at 3-41 as we head into the weekend. That’s down a penny from one week ago, but 25 cents more than what we were paying one year ago.

Here in San Antonio, the average price per gallon is down 6 cents from last week to 3-45. That’s 36 cents more than what we were paying one year ago.

While there was a small dip in prices this week, the auto club warns, the potential for higher gas prices is lingering.

That’s due to higher crude oil prices and a decrease in regional gasoline supplies.

However, refineries will be switching to the winter blend of gasoline which is a lot cheaper to produce, meaning as the temperatures drop, gas prices will fall as well.

The difference between summer- and winter-blend gasoline involves the fuel’s Reid Vapor Pressure , 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.

Summer-blend gas contains two percent butane, but that percentage is higher in the winter blend. Butane is used as lighter fluid and is a secondary ingredient in fuel canisters used for gas grills and camping. As a fuel, butane is less expensive than other gasoline components, but its high volatility limits how much can be included in summer-grade fuel.