Wisconsin Sees Highest Year-Over-Year Increase in Diesel Prices

Friday, October 2nd, 2026 -- 10:00 AM

(Caden Perry, Milwaukee Journal Sentinel) Wisconsin has seen the highest year-over-year increases in diesel prices out of any state in the nation, new data shows.

According to Caden Perry with the Milwaukee Journal Sentinel, Wisconsin's regular gas prices are more than 50% higher than the same time last year, and diesel prices almost 90% higher, according to GasBuddy's petroleum analyst Patrick De Haan.

As of Sept. 29, a gallon of diesel gas in Wisconsin cost $6.47 on average. That is 86.5% higher than the 2025 average of $3.00 per gallon. Other states get close to this markup, but Wisconsin claims the top spot.

The latest price of $6.47 per gallon of diesel is a decrease from the all-time record set on Sept. 22 at $6.62 per gallon. Since the Exxon Mobil refinery restarted operations in Joliet, Illinois, diesel prices in the Great Lakes service region have recovered.

Wars in Russia and Iran continue to keep prices inflated beyond fall norms. On Sept. 20, Russia extended its diesel export ban until at least the end of October, Houthi activity around Saudi Arabia has caused uncertainty on Red Sea exports, and the Strait of Hormuz near Iran remains closed.

Wisconsin fares slightly better in regular gas compared to other states, but is still in the top five for inflated prices among other states. Prices are still more than double where they sat in 2025. On Sept. 29, a gallon of regular gas cost an average $4.279 across Wisconsin, according to GasBuddy's data.

That's 51.6% higher than Sept. 29, 2025's $2.82 per gallon. Wisconsin's all-time gas record of $4.92 per gallon is still unbeaten from the April 2022 spike caused by the start of the Ukraine-Russia war.

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