26 times in 27 days gas has set a record high, this is just incredible. CNNMoney.com Gas prices set a new record high at $3.978 a gallon - AAA Tuesday June 3, 11:11 am ET By Catherine Clifford, CNNMoney.com staff writer Retail gas prices set a record high for the 26th time in the past 27 days, motorist group AAA's Web site showed Tuesday. AAA reports the national average price for a gallon of regular unleaded gasoline rose to $3.978. That was up 0.3 cent from the $3.975 mark set Sunday and matched Monday, the first time pump prices didn't rise since May 7. The AAA survey shows gas prices are up 10% from a month ago and almost 26% higher from year-ago levels. This record runup of prices at the pump is happening at the start of the summer driving season, which unofficially began over Memorial Day. The average price for gas has passed the $4 a gallon mark in 12 states, as well as in Washington, D.C. Those states where gas has already passed the $4 threshold are as follows: Alaska, California, Connecticut, Hawaii, Illinois, Michigan, Nevada, New York, Oregon, Rhode Island, Washington, and West Virginia. The most expensive state for buying gas is California, where a gallon of regular unleaded costs an average of $4.274, according to AAA. The second most expensive state is Connecticut, where a gallon of gas costs $4.260. The least expensive state for purchasing gas is South Carolina, where a gallon costs $3.795 a gallon on average. The second least expensive state for gas is Missouri, where a gallon runs $3.80 a gallon. Gas prices have been pushed to record levels in the past year on the back of record oil prices. As the price of crude oil has more than doubled, gas prices have increased by almost a quarter.