Feb. 26 (UPI) -- U.S. gasoline prices saw their biggest weekly gain so far this year, and drivers' fuel spending likely won't ease any time soon as refiners start preparing for the warmer weather season, analysts said.
"Pump prices have increased around the country as refineries gear up for spring gasoline production and maintenance season," according to the AAA's weekly fuel price and analysis report released Monday.
At $2.39 per gallon, the national fuel price average is eight cents more expensive than in the previous week, representing most of the 12-cents-per-gallon, month-over-month increase. Prices are currently nearly 12 cents per gallon lower on year, according to the AAA.
This has occurred despite decreasing demand, AAA said. Gains in crude prices and coming seasonal changes pushed prices higher, AAA said.
Gas Buddy, which also tracks weekly fuel price changes, also estimated the national gas price average at $2.39 per gallon, adding that the average price of diesel saw a weekly 3.7 cents per gallon gain to $2.97 per gallon.
Prices will rise "into March and even April as seasonal trends kick into high gear," Gas Buddy added. However, it projected they are likely to stay lower than last year.
Gasoline prices in the Great Lakes and Central region rose as much as 15 cents per gallon, with Minnesota seeing a rise of 15 cents per gallon, as well as Iowa and Indiana seeing rises of 12 cents per gallon.
In the South and Southeast, New Mexico and Florida led weekly increases with 13 cents per gallon and 11 cents per gallon rises, amid an inventory decrease of nearly a million barrels per day for the region.
In the Mid-Atlantic and Northeast, prices rose 11 cents per gallon in the context of "a susbstantial drop in inventories." However, four states, led by Massachusetts with a 3 cents per gallon drop, saw declines.
Utah, in the Rockies, saw a similar decrease of three cents. The Rockies fuel inventories saw a small draw. "Overall, the region's gas prices are only more expensive than states in the South and Southeast region," with a healthy overall supply.
In the West Coast region, which carries the most expensive prices in part due to stricter emission regulations, prices mostly declined with Alaska seeing the biggest weekly drop of 4 cents per gallon. At $3.28 per gallon, California is the most expensive market, the AAA said.
Fuel sold as gasoline in the pump is a combination of either RBOB, Reformulate Gasoline Blendstock for Oxygenate Blending, or CBOB, Conventional Blendstock for Oxygenate Blending. Some states use RBOB and others CBOB. California mandates a special formula named CARBOB.
These blendstock products are all naphtha obtained from crude oil. Then about 10 percent ethanol, or more, which is an oxygenate, is added so that the ending emission is cleaner.
RBOB gasoline futures for March delivery were quoted Tuesday morning at $1.56 per gallon. This compares with $1.57 per gallon on Feb.19 also for March delivery, according to CME Group data.
Ethanol, which is alcohol that in the United States is mostly derived from corn, was quoted Tuesday at $1.34 for March delivery, up from $1.31 per gallon on February 19.
"Traditionally, gas prices at their lowest during the first week of February and then begin to climb, often peaking right before Memorial Day," according to recent commentary by NACS, an organization that represents 80 percent of the country's retail fuel sales
"Seasonal gasoline demand is a factor, but there also are other market-related events that historically impact gas prices in the springtime," NACS said.