How gas prices have changed in Sagadahoc County, Maine in the last week

A combination of increased demand at the pump and the annual switchover to more expensive, but lower-emission summer fuel blends are driving the national cost for a gallon of gasoline higher this week.

The national average has risen several cents from a week ago and remains below the levels it was this same time last year, according to GasBuddy. Metros on the West Coast, as well as Illinois, Michigan, and Pennsylvania, are seeing the highest gas prices in the nation to begin this week.

A rise in the utilization of refineries producing gasoline this spring after a particularly difficult winter may be helping keep prices lower for travelers. When refinery utilization drops, it can raise the cost of gas; cold weather and storms took some plants offline this winter season.

Stacker compiled statistics on gas prices in Sagadahoc County using data from AAA. Gas prices are current as of March 11.