(WJBK) - AAA Michigan says gas prices statewide have risen by about 11 cents a gallon in the past week.
The Dearborn-based auto club says early Monday the average price for self-serve regular unleaded gasoline was about $2.07 per gallon. That's about 33 cents less than it was at the same point last year.
FOX 2's Roop Raj reports the gas prices have increased because refineries are switching from their spring blend to their summer blend, which causes supplies to fluctuate during this time.
Patrick DeHaan with GasBuddy.com tells Roop authorities passed a clean air act in the 1990s which called for the summer blend to be enacted.
The lowest average price was about $2.02 per gallon in the Detroit area, while the highest average was about $2.14 per gallon in the Jackson area.
AAA Michigan surveys daily fuel prices at 2,800 gas stations across the state.
The Associated Press contributed to this report.