This fall season was supposed to bring some relief at the gas pumps, but millions of American drivers are starting the season paying even higher prices to fill up their tanks.

The national average for regular gasoline reached $4.3672 per gallon on September 16, compared with $4.2245 last week and $3.1862 a year ago, according to AAA.

  • Why it matters: September usually marks the transition to winter gasoline, which is less expensive to produce, but this year other factors are offsetting those potential savings.

Winter Gasoline Arrived Early, but Prices Didn’t Budge

The EPA even moved up the transition this year: beginning September 1, it allowed temporary flexibility in federal volatility requirements to increase gasoline supply.

The exemption remained in effect through September 15. As of Tuesday, September 16, refineries can now report fuel that meets winter specifications as winter gasoline.

  • The fact: despite these measures, a gallon of regular gasoline now costs about 30 cents more than a month ago and approximately $1.18 more than a year ago, according to AAA.

AAA had already warned on September 10 that the national average was rising as oil prices climbed above $100 per barrel amid volatility related to the Strait of Hormuz.

What do you think will happen to gas prices this fall?

Refinery Disruption Complicates Gas Prices in the Midwest

This pressure is compounded by an unexpected disruption at ExxonMobil’s refinery in Joliet, Illinois, after a power outage halted production over the weekend.

Patrick De Haan, head of petroleum analysis at GasBuddy, told The Center Square that fully restarting the facility could take several days while safety assessments and potential damage are evaluated.

The impact coincides with strong regional price increases. Michigan, Wisconsin, and Illinois were among the states that registered significant gas price hikes over the past week, according to information provided by The Center Square.

  • The diesel situation is adding to the pressure: the national average reached $6.3103 on Wednesday, its highest recorded level according to AAA.

When Can Relief at the Gas Pumps Be Expected?

  • The key: switching to winter gas does not automatically guarantee a drop in the price consumers see.

The final cost also depends on oil, available inventories, refinery operations, demand, and potential regional disruptions.

There are even huge differences within the United States: while California averages $6.0440 per gallon, Texas registers $3.8788, according to AAA.

For now, the expected seasonal relief is competing with much stronger forces. For drivers, the arrival of fall is still not translating into a lower bill when filling up their tanks.