Gas prices have increased an average of 9 cents in Illinois and Northern Indiana during the past month. High wholesale costs for gasoline and a higher demand during the summer months contributed to this increase.

According to AAA Chicago's most recent fuel gauge report, the average price of regular unleaded gasoline in Illinois now averages $1.60 per gallon, which is up 10 cents from this time last month and 10 cents from last year's prices. In northern Indiana, gas prices now average $1.46, which is up 7 cents from last month and up 3 cents from last year's prices.

In Cook County, self-serve regular unleaded gasoline now averages $1.73 per gallon, which is up 11 cents from last month.

In DuPage County, self-serve regular unleaded gasoline now averages $1.65 per gallon, 12 cents higher than May prices.

In Kane County, self-serve regular unleaded gasoline averages $1.63 per gallon, 13 cents higher than May prices.

In Lake County, self-serve regular unleaded gasoline averages $1.64 per gallon, 11 cents higher than May prices.

In McHenry County, self-serve regular unleaded gasoline averages $1.64 per gallon, 14 cents higher than May prices.

In Will County, self-serve regular unleaded gasoline averages $1.65 per gallon, 16 cents higher than May prices.

"In addition to higher wholesale prices, refineries must contend with reformulated gasoline standards in order to meet Midwest guidelines," said AAA Chicago spokesman Steve Nolan. "This is also a contributing factor to the higher gas prices."

AAA Chicago offers automotive, travel, insurance and financial services. It is part of The Auto Club Group (ACG), the largest affiliation of AAA clubs in the Midwest, with 4.1 million members in eight states. ACG clubs belong to the national AAA federation, a not-for-profit organization, with more than 45 million members in the United States and Canada.

Source: AAA Chicago