With the summer driving season now underway, the nation's average price of gasoline declined 3.9 cents from a week ago to $3.51 per gallon.
The national average diesel price fell 3.4 cents last week and is $3.88 per gallon.
However, GasBuddy's Patrick De Haan warns OPEC could change the course of fuel prices this summer. OPEC+ agreed Sunday to additional production cuts, while Saudi Arabia is going above and beyond and cutting July production.
As a result, De Haan says, "oil prices are likely to see upward pressure as global supplies, which have remained tight, promise to become even tighter as a result."
Oil prices could rally this week and push fuel prices higher, but De Haan says any rise in average prices should be fairly small. U.S. retail gasoline demand saw a 2.3 percent fall last week, with the most common U.S. gas price at $3.39 per gallon.