The average price for a gallon of unleaded in the Cincinnati area jumped more than 40 cents overnight to $4.39. WLWT reported the spike on Friday, Oct. 23, citing AAA data.

That $4.39 already reflects Ohio's 38.5-cent-per-gallon gas tax suspension, which took effect Oct. 4 and runs through Jan. 2, 2027. Without the tax break, drivers would be paying closer to $4.78.

Warren County had some of Ohio's lowest prices as recently as Oct. 19, when the county average sat at $3.89, according to the Dayton Daily News. No Warren County-specific figure was available for Oct. 23, but the regional jump suggests local pumps saw a significant increase as well.

WLWT reported that the exact cause of the overnight surge was not clear, but that analysts pointed to the ongoing war with Iran, the war between Russia and Ukraine, and broader disruptions to oil and gas shipping lines as contributing factors.

A Midwest refinery problem added to the pressure. Industry analyst Tom Kloza attributed regional overnight price increases to problems with a 50,000-barrel-per-day catalytic reformer at ExxonMobil's Joliet refinery in Illinois, which shut down Oct. 20, according to Hoodline, citing the Daily Caller. An ExxonMobil spokesperson said Oct. 21 that the company was working to resolve the issue but gave no restart timeline.

The Joliet plant, a 275,000-barrel-per-day facility, had already suffered a total power outage on Sept. 13 that forced an emergency shutdown, the Lake Forest Journal reported. That outage coincided with planned maintenance at the Cenovus refinery in Lima, Ohio, which took another 185,000 barrels per day offline starting in September, according to the same report.

Wholesale gasoline prices in the region climbed another 25 cents a gallon on the morning of Oct. 22, Kloza reported, according to Hoodline.

Prices also rose in neighboring states. Indiana climbed about 10 cents to $3.98 per gallon, and Kentucky jumped to $4.04, WLWT reported.

The tax holiday has not kept pace with the forces pushing prices up. One week into the suspension, on Oct. 7, Ohio's average was $3.71, according to GasBuddy data reported by Fox 19. By Oct. 16, the statewide average had climbed to $4.11. GasBuddy lead petroleum analyst Patrick De Haan said the tax holiday did not freeze gas prices and that factors like higher oil trading and refinery outages would still push costs up, Fox 19 reported.

"If we see some improvement in tensions there, then we could see some relief," De Haan told the Chicago Tribune, as quoted by the Lake Forest Journal. ExxonMobil has not disclosed a restart date for the Joliet reformer unit.