By Charles Kennedy of OilPrice.com

U.S. gasoline prices rose for a second week in a row, to average $3.40 per gallon on Monday, up by 6.2 cents from a week ago, amid rising demand, ongoing refinery maintenance, and the switch to summer gasoline, GasBuddy said today.

Still, the national average price of regular gasoline is 4.5 cents per gallon lower than a year ago, said GasBuddy, which has compiled price data from more than 12 million individual price reports covering over 150,000 gas stations.

The national average price of diesel, on the other hand, has fallen by 1.3 cents in the past week and stands at $4.02 per gallon on Monday, which is 30 cents lower than this time last year, according to GasBuddy’s data.

American drivers could be in for some relief in the coming weeks, due to a rise in U.S. refinery utilization in the most recent week, and a possible earlier end to refinery maintenance, said Patrick De Haan, head of petroleum analysis at GasBuddy.

“The national average price of gasoline has seen a continued but measured rise compared to last week, but the pace of increases has slowed slightly in the last few days. With government data showing a rise in refinery utilization last week, there may be some good news on the horizon for drivers,” De Haan said.

“Much of the seasonal rise that happens this time of year is a culmination of refinery maintenance, the switch to summer gasoline, and rising demand,” the expert noted.

The changeover is still ongoing so the upward trend is likely to persist, but higher refinery output could ease some of the upward pressure on gasoline prices, according to De Haan.

More expensive international crude prices are also to blame for the rise in U.S. gasoline prices, AAA said last week.

“Spring is nearly here, with longer days, better weather, and more opportunities to hit the road,” AAA spokesperson Andrew Gross said.

“And we are seeing this reflected in rising gasoline demand. But remember, we see this trend every year.”