Affordability is seen as one of voters' top issues heading into the 2026 midterm elections. And gas prices — one of the items where consumers are getting squeezed the most — are expected to remain elevated through Election Day.

Speculators on prediction market platform Kalshi give an 87% chance that the AAA national average for gas prices will remain above $4 per gallon on Nov. 3.

But while they expect prices to stay above that mark, they do think there's a chance they'll come down from the levels where they currently are, giving just a 42% chance the average is above $4.25 on Election Day. As of Thursday, the national average is currently at $4.36 per gallon.

Gas prices peaked at an average of $4.56 per gallon in late May, following an initial spike in March after the start of the Iran war and the latter country's closure of the Strait of Hormuz, a critical passageway for oil exports from the Middle East. They then fell to as low as $3.79 per gallon in early July before rising again throughout the rest of the summer.

Diesel prices hit new peaks in September, though, reaching almost $6.53 per gallon on Sept. 22. Prices have since fallen to $6.28, though traders on Kalshi place 68% odds that figure remains above $6 per gallon on Nov. 3.

Rising diesel prices have a particular impact in states with larger agriculture industries, such as Iowa and Kansas, and states such as Alaska that rely on diesel fuel for electricity. All three are home to competitive races for the U.S. Senate this November.

As gas prices have remained elevated, Democrats' chances for flipping the Senate have improved. Traders on Kalshi give the party 63% odds of taking the upper chamber from Republican control.

Disclosure: CNBC and Kalshi have a commercial relationship that includes customer acquisition and a minority investment.