Average retail gasoline prices in Michigan have risen 24.6 cents per gallon in the past week, averaging $3.98 per gallon Sunday. This compares with the national average that has increased 9.3 cents per gallon in the last week to $3.60 per gallon, according to gasoline price website MichiganGasPrices.com.

Including the change in gas prices in Michigan during the past week, prices Sunday were 22.9 cents per gallon higher than the same day one year ago and are 45.2 cents per gallon higher than a month ago. The national average has increased 19.1 cents per gallon during the last month and stands 6.5 cents per gallon lower than this day one year ago.

“Watching the national average last week, one might have expected war broke out in the Middle East or a major hurricane shutting down production, neither of which happened, yet gasoline prices spiked,” said Patrick DeHaan, a senior petroleum analyst for GasBuddy.com. “The scary thought is what may happen to gasoline prices should one of the two actually take place. The Great Lakes was hosed with refinery issues and a major oil pipeline issue, and, while other regions saw increases, they paled in comparison to those in the Great Lakes states.

“The good news for motorists is that the end to the summer driving season and change to winter-spec fuel is in view, which will likely put downward pressure on gasoline prices,” DeHaan said.