Hawai'i's wholesale gas cap will increase for a second consecutive week on Monday as refiners pass along higher crude-oil prices and colder-than-normal weather boosts demand for heating oil on the Mainland.

Recent market activity points to a 4-cent to 5-cent increase in the state's price ceiling next week, according to Advertiser calculations. The state tomorrow will announce a new price cap to take effect Monday.

The increase will be added atop a 7-cent hike this week. The state limits only wholesale prices but Hawai'i's retail gasoline prices generally follow the wholesale cap.

The state has the highest gas prices in the nation and began capping wholesale prices Sept. 1 to bring them more in line with prices on the Mainland.

In September, the price of a gallon of regular reached $3.68. As of Sunday night the statewide average was $2.647, according to the American Automobile Association.

"Any increase in Hawai'i prices hurts a little, but after the recent increases we're a little acclimated," said Kapahulu resident Darryl Tagami, 50. "The shock isn't there anymore."

Should pricing trends continue through today the cap will be raised to its highest level since Nov. 13.

Proponents of the gas cap argued the law tying Hawai'i's wholesale gas prices to the Mainland was needed because local gasoline prices went up steadily but rarely declined when they fell in other states.

Crude oil prices crept over the $60 a barrel level on Thursday and closed at $61.30 yesterday on the New York Mercantile Exchange. That was accompanied by below-average December temperatures in more than three-quarters of the U.S., forecaster AccuWeather Inc. told Bloomberg News.

"People are just speculating that we're going to have a long, cold winter," said Mark Waggoner, president of Excel Futures Inc. in Huntington Beach, Calif.

The higher prices may not be putting a dent in people's driving habits locally, though. State tax data show motorists here used 36.8 million gallons of gas in October, or 7.2 million gallons more than a year earlier when regular ranged between $2.36 and $2.40.

"It's still a pretty cheap way to get around if you think about it," said Ron Hoeke, 32, a North Shore resident who commutes to Kewalo Basin each day for work. He said some Europeans pay twice as much. Hoeke favors levies that could fund research and development of alternate fuels and mass transit.

The U.S. Energy Department yesterday forecast oil prices will remain near or above the $50 a barrel level for years and result in drivers looking at more fuel-efficient cars and alternative fuels. The agency's report said oil prices in coming years will be in the mid-$40 range or higher and average $54 a barrel by 2025.

The forecast also projected increasing use of ethanol and biodiesel fuels along with hybrid gasoline-electric cars.

The state's gasoline cap is computed using wholesale prices during a five-day period in New York, the Gulf Coast and Los Angeles.

The Advertiser's preliminary calculation is based on four-days of market data from those markets as reported by Bloomberg and may be different by a few cents from the state's projections, which use prices supplied by the Oil Price Information Service.

Reach Greg Wiles at gwiles@honoluluadvertiser.com.