By John Dodge

CHICAGO (CBS) — While motorists around Chicago are well aware of plummeting gasoline prices, they may be surprised to learn that the average cost of a gallon of petrol is actually below the national average.

That’s pretty rare, says Patrick DeHaan of Gas Buddy.

Typically, gasoline prices around Chicago rank among the highest in the country–a combination of higher taxes and the required higher-priced gasoline blends.

This is only the eighth time in 10 years that local prices were cheaper than what drivers typically pay elsewhere. The low cost may be attributed to the fact that Midwest refineries are producing an ample supply.

Currently, the average price per gallon in Chicago stands at $1.82, with some stations selling for $1.50 or less.

In Northwest Indiana, most stations are charging $1.50-$1.60.

Earlier this week, DeHaan said prices may drop further when gas stations start trying to get rid of the current winter mix of gasoline to make way for the summer blend they are required to sell in Chicago and other major cities starting in the spring.

DeHaan wouldn’t be surprised to see some isolated gas stations on the outer fringe of the Chicago metropolitan area charging as little as $1.29 per gallon at some point in the weeks or months ahead.