Oil refinery problems in California and the Great Lakes area are being blamed for a recent spike in gasoline prices.

Average retail gasoline prices in Connecticut have risen 5.8 cents per gallon in the past week, averaging $3.93 per gallon Sunday. This compares with the national average that has increased 5.4 cents per gallon in the last week to $3.67 per gallon, according to the website ConnecticutGasPrices.com.

With $4.19 for regular, the Shell at Danbury Road and Mountain Road has the third highest price in the state, according to the website. The highest is $4.74 per gallon at a Mobil on Post Road East in Westport.

The cheapest reported gas price in Wilton is $3.93 for a gallon of regular at CITGO on Danbury Road near Catalpa.

Including the change in gas prices in Connecticut during the past week, prices yesterday were one cent per gallon lower than the same day one year ago and are 25.2 cents per gallon higher than a month ago. The national average has increased 24.8 cents per gallon during the last month and stands 5.7 cents per gallon higher than this day one year ago.

"The national average has spiked 25-cents per gallon just in the last month, thanks to an onslaught of refinery problems — mainly in the Great Lakes and California," said GasBuddy.com Senior Petroleum Analyst Patrick DeHaan. "While these situations are temporary in nature, it goes to show this nation's dependence on domestic refineries. While oil prices have gained in recent days, there is some light at the end of the tunnel for motorists: driving season will be over in less than a month and soon thereafter the EPA also relaxes gasoline mandates, meaning cheaper winter fuel," Mr. DeHaan said.

GasBuddy operates ConnecticutGasPrices.com and over 250 similar websites that track gasoline prices at over 140,000 gasoline stations in the United States and Canada. In addition, GasBuddy offers a free smartphone app which helps motorists find gasoline prices in their area.