Gasoline is more expensive today than it has been all year, but the cost at the pump this Memorial Day weekend will still be the lowest it has been over the summer kickoff holiday in 11 years.
On Wednesday, the average price for a gallon of regular unleaded gas in Tampa was $2.13, according to gasbuddy.com, up about 2 cents from last week and 15 cents from last month.
The national average was $2.29 per gallon, a 7-cent increase per gallon from last week and a 15-cent increase from last month, according to AAA. Florida's average prices have risen nine days in a row.
National gas price averages have increased every day for about two weeks, but are still lower than last year's price of about $2.60 per gallon, said Mark Jenkins, spokesman for AAA.
A recent increase in the price of oil, a switch to a new "summer blend" of gasoline and a rise in demand are the likely culprits behind the spike, Jenkins said.
"More people are driving and, in fact, are pushing the record for high levels of traffic," Jenkins said. "With gas prices being so low, it's more enticing for people to take a road trip."
AAA estimates that more than 38 million Americans will travel over Memorial Day weekend, an increase of 700,000 over last year's numbers. That's the highest volume reported by AAA since 2005 and the second-highest travel volume ever reported by the organization. Of those 38 million, about 89 percent plan to drive, according to AAA.
Wildfires in the Canadian province of Alberta have also caused some interruptions in oil supply, Jenkins said. When the price of oil will stabilize is "anyone's guess," he said.
The rise in prices is somewhat cyclical, said Kevin Doyle, executive director for the consumer advocacy group Consumer Energy Alliance.
Gas prices usually rise as seasons change because of an Environmental Protection Agency regulation that requires manufacturers create a "summer blend" of gas with lower emissions. Refineries empty their gasoline reserves before switching to the new blend and use the break to complete any lingering maintenance, which cuts down on gasoline production, Doyle said.
Refineries have to switch to the summer blend by June 1.
Prices should begin to stabilize after Memorial Day weekend and likely will remain low.
"A lot of that has to do with Americans producing more energy in the U.S. and Canada," Doyle said. "The more we produce here, the more gasoline we have in the market, which cuts prices for everyone."