Gas prices are falling across the U.S., with the national average price for a gallon of regular unleaded gasoline at $3.57 per gallon on June 24, according to AAA’s latest Fuel Gauge Report.

This price is down four cents from the prior week, and seven cents less than the price a month ago. Despite recent declines in gas prices, this national average price is still 15 cents higher than on the same day last year.

For diesel prices, the U.S. Energy Information Administration (EIA) said the average price on June 24 was $3.83 per gallon, which is basically flat from the week before (down only 0.003 cents). This price is up 16 cents from the same day a year ago. On a regional basis, retail diesel prices are also basically flat, according to the EIA, with the largest increase being 1.3 cents in Calif. and the largest drop being 1.2 cents in the Midwest and Rocky Mountain regions. 

On a regional basis, gas prices are up in 14 states and in Washington D.C., with the highest increases (more than eight cents) in California and Nevada. In the Great Lakes states, which saw much higher prices earlier this year, prices have been falling, with the average price since last week in Mich. down 30 cents, down 27 cents in Ind., and down 24 cents in Ohio, and Wis.

AAA said that although prices should keep falling through the end of June, they could increase in July as the summer driving season kicks into high gear. Last year, the national average price went up 17 cents per gallon, and 16 cents per gallon, in 2011 and 2012, respectively.

The company added that lower crude oil prices could help keep prices down. One factor influencing oil prices is the U.S. Federal Reserve, which has been purchasing bonds as part of its quantitative easing program. Since oil prices are measured in dollars, a slowing in quantitative easing would strengthen the dollar, thereby making oil a less attractive investment (more expensive for investors who hold foreign currencies). This would help push oil prices down. AAA noted that after the price of a barrel of West Texas Intermediate crude oil hit $98.44 last Tuesday, it fell to $93.69 at the end of the week after the Federal Reserve Chairman made statements regarding potentially slowing the rate of its quantitative easing program. That said, three closed pipelines in Alberta due to flooding in Canada put pressure on prices, and at the end of trading on the NYMEX, the price of a barrel of WTI had increased by $1.49 to $95.18.

The chart from AAA below shows the trend in the national average retail gas price between Jan. 1, 2011 and June 24, 2013.