Gas prices across Greater Cincinnati surged more than 40 cents overnight, pushing the average to $4.39 a gallon even with Ohio's gas tax suspension in effect.

AAA reported the spike on Friday, Oct. 23, according to WLWT. The $4.39 average already reflects the 38.5-cent-per-gallon discount from the state's 90-day gas tax holiday, which Gov. Mike DeWine signed into law Oct. 1. Without that tax break, drivers would be paying closer to $4.78.

Some stations were charging far more. The Cincinnati Enquirer reported the Sunoco on Madison Road in Madisonville hit $4.69 a gallon on Oct. 23. Several area stations were at $4.49.

Cincinnati's average jumped about 42 cents from Oct. 22 and sat roughly $1.34 higher than a year ago, when the average was about $3.05, according to the Enquirer. The national average stood at $4.29.

Why prices spiked

No single cause explains the overnight jump, WLWT reported. Experts pointed to the war with Iran, the war between Russia and Ukraine, and broader disruptions to global oil and gas shipping.

A refinery problem added regional pressure. The Daily Caller reported Oct. 22 that a 50,000-barrel-per-day catalytic reformer at ExxonMobil's Joliet, Illinois, refinery went down. That unit converts low-octane fuel into higher-octane gasoline. An ExxonMobil spokesperson told CNN the company was working to resolve the issue but gave no timeline for a fix, the Daily Caller reported.

Tom Kloza, chief energy advisor at Gulf Oil, said the Joliet breakdown shows American refining has no margin for error. Wholesale prices in the region climbed another 25 cents a gallon on Oct. 22, Kloza said, according to the Daily Caller.

He predicted the spike would not last. "While I do not believe these crazy numbers can be sustained, they are pointing to $5/gallon prices in many cases," Kloza said.

Tax holiday hasn't kept pace

Ohio lawmakers approved the 90-day gas tax suspension Sept. 30, eliminating the 38.5-cent gas tax and 47-cent diesel tax through Jan. 2, 2027, according to WOSU. The state estimated the move would cost $726 million, covered by general fund reserves.

But rising oil prices have eaten into the savings. Patrick De Haan, head of petroleum analysis for GasBuddy, told Spectrum News 1 on Oct. 20 that oil prices had jumped more than $10 a barrel over the same period, offsetting much of the tax relief at the pump.

Even so, De Haan said Ohio's prices remain lower than in nearby states without a gas tax suspension. Michigan was averaging about $4.46 a gallon as of Oct. 20, Spectrum News 1 reported.

Where to find cheaper gas

The Enquirer reported the lowest price in the Cincinnati area on Oct. 23 was $3.57 a gallon at QuikTrip on Progress Place in Springdale. Closer to Anderson Township, the Sunoco at 690 Wooster Pike was listed at $3.89.

Ohio's gas tax suspension runs through Jan. 2, 2027. Analysts told Spectrum News 1 that drivers should expect prices to rise again two to three days after that date.