| General Information

Questions About Gas

Every year, gas prices are higher in the summer than they are in the winter, and if you’re a fleet owner, you’ve probably noticed the need to increase your gas budget during the warmer months. However, have you ever wondered why this happens?


As you may have guessed, part of the reason is because gasoline is usually in higher demand during the summer. Many people take their vacations in warmer months, and therefore use more fuel than in the winter. If suppliers only produce a certain amount of gasoline, it’s necessary to increase the price.

Refinery Maintenance

During the spring months, oil refineries often schedule their refinery maintenance. This means that they shut down their refineries, which limits fuel supplies until late May. This shut down also contributes to the increase in gas prices; less availability means a price hike.

Reformulated Fuel Blends

The main reason gas prices are different is because different gasoline is used in the summer than in the winter. Under the 1990 Clean Air Act, the Environmental Protection Agency requires gas stations to use reformulated fuel blends during the summer (April through September). This was put into effect because winter fuel must be able to evaporate at a lower temperature than summer fuel.

It was also put into effect to lower the pollution and smog during the “ozone season” (a.k.a. summertime). Because summer fuel burns cleaner, it produces less pollution. In turn, however, it’s more expensive to produce, so┬áconsumers must pay a higher price for it.

More About Reformulated Fuel Blends

To explain the difference between summer fuel and winter fuel even further, it’s good to know what Reid Vapor Pressure (RVP) is. RVP is the measurement of how fast fuel evaporates at a certain temperature. In order for a car’s engine to operate properly in cold weather, the car’s gas must evaporate at a lower temperature, and therefore have a higher RVP. During the summer, gas must have a lower RVP in order to not evaporate in higher temperatures.

Because of this difference in gas, the EPA has claimed that 75 million Americans now breathe cleaner air.