CHICAGO (CBS) — If you have to fill up your car’s gas tank on Monday, you may be shocked at your total.

Drivers are paying 40 cents more for a gallon of gas since just last month, CBS 2’s Susanna Song reports.

If you haven’t been at the pump for some time, you’re in for a surprise—drivers can expect to pay around $4 or more per gallon.

For example, a gallon of regular unleaded at the BP on Roosevelt and Wabash costs $4.19. The average in Chicago is $4.10, up 12 cents in the past week, according to Gas Buddy.

According to Triple A, the national average is up more than 40 cents from this time last month.

This time last year, a gallon of gas in the Chicago area cost $3.54.

The spike comes at the same time that paychecks are getting smaller. Most Americans are taking home less money after the payroll tax cut expired.

What’s behind the higher prices?

The price of crude has jumped 10 percent in the last two months.

Several refineries have also shut down for maintenance before switching to summer gasoline.

There is a silver lining.

Chicago no longer has the highest gas prices in the nation.

It actually ranks tenth, behind locations in California and Hawaii.

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