CHARLESTON, S.C. (WCBD)- After weeks in decline, the cost of gas in South Carolina has climbed back over the $3 mark.

The state gas price rose 4.2 cents in the last week and South Carolinians can now expect to pay $3.02 per gallon at the pump on average, based on a survey from GasBuddy of 3,028 gas stations across the state.

Gas prices in South Carolina are 10.4 cents per gallon lower than a month ago and stand 84.5 cents per gallon lower than a year ago.

The survey found that the cheapest gas in the state is priced at $2.66 per gallon while the most expensive is $3.49 per gallon, a difference of 83.0 cents per gallon.

The national average price of gas rose by 3.5 cents, averaging $3.36 per gallon today. The national average is 6.5 cents per gallon lower than a month ago and stands at 69.3 cents per gallon lower than a year ago.

“The national average rose last week as the transition to summer gasoline has now started across the entire country,” Patrick De Haan, head of petroleum analysis at GasBuddy said. “The higher cost of these various blends is being passed along to motorists, as we see every year ahead of the summer driving season.”

De Haan noted that gas prices will continue to trend upward through the spring and a $4 per gallon national average is possible around Memorial Day.

“Some regions are moving to the required summer gasoline in different steps than others, and the fragmentation of required blends absolutely plays a role in these price increases,” he explained. “Logistical challenges in making the transition during a time when refiners are also doing maintenance work can create hotspots and lead to noticeable jumps in prices during the spring.”

The national average price of diesel fell 4.6 cents in the last week and now stands at $4.34 per gallon.