(CNN) - Gas prices are taking a bigger bite out of motorists nationwide.
Triple-A says the average price for a gallon of regular unleaded gas is now $2.75.
That's up 11 percent in the last month.
“Gas prices are increasing across the country, but these changes vary by region,” said Jeanette Casselano, AAA spokesperson. “On the week, motorists in the West Coast, Rockies, Great Lakes and Central regions are seeing some of the largest weekly increases while prices mostly east of the Mississippi have made more moderate jumps.”
Prices are highest in California, Hawaii, Washington, Oregon, Nevada and Alaska.
The average gas price in those six states are more than $3.00 a gallon.
And in California alone, the statewide average is $3.83 a gallon.
Analysts blame the price hikes on unplanned refinery maintenance at several locations.
“The western half of the country hasn’t added any refining capacity this century,” said Tom Kloza, head of energy analysis for the Oil Price Information Service. “It’s been a cluster of difficulties but not disasters hurting supplies, particularly out in the West.”
Kloza said $4-a-gallon gas will be common in California and other western states in the coming weeks.
Western states are particularly vulnerable to this as they have less refining capacity than other parts of the country.
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