Earlier this week AAA reported in its weekly Fuel Gauge Report that gas prices have risen since last week, most dramatically in the Midwest. The average price for a gallon of regular unleaded gasoline was $3.65 on Monday, May 20, which is 7 cents more than Monday, May 13. AAA said this is the largest increase since February and the highest average price at the pump since March. AAA said refinery maintenance and tight supplies are driving these increases.

In the Midwest and on the West Coast, prices have increased the most. In Minnesota, the average price has risen 68 cents during the last two weeks (May 6 to May 20) and it's up 63 cents in North Dakota during this period, for example. The average gas price in Minnesota was $4.197 on May 23, according to Gasbuddy.com.

Three other states, Iowa, Neb., and Okla., saw prices increase by more than 50 cents during this two-week period. In 12 Midwestern states and in Okla., AAA says drivers will pay at least 10 cents per gallon more they did on Memorial Day in 2012 (the price was $3.64 on May 28, 2012).

States with the highest average gasoline prices on May 20 included Hawaii, at $4.35 per gallon; Minn., at $4.27; N.D., at $4.23; Alaska and Calif. at $4.06; Ill. and Neb., at $4.05; Iowa, at $4.02; Wash., at $4; and Ore., at $3.98.

As for the price of oil, the price of West Texas Intermediate (WTI) crude oil settled at $96.71 per barrel on May 20, which is the highest price for WTI in more than six weeks, according to AAA.