Hawai'i's wholesale gas prices are poised to drop next week, the seventh time since Oct. 16 that prices have declined.

Drivers could see a decline of 2 cents a gallon, according to Advertiser calculations. It could result in gasoline prices at O'ahu's most inexpensive stations falling to prices not seen in five months.

The maximum price wholesalers and distributors can charge has tumbled about 89 cents during the past six weeks as prices on the Mainland decline. The cap went into effect on Sept. 1 and ties Hawai'i's wholesale gas prices to those in New York, the Gulf Coast and Los Angeles.

"The gas cap was a good idea," said Waikele resident Jessica Bauman, 23, who parked her Toyota pickup truck in August and began car pooling to get to her job as an administrative assistant in downtown Honolulu. "It's good it's going down."

The price of regular is still 12.6 percent higher than a year earlier, and 29 percent more than two years earlier. Bauman said the higher prices will affect her Christmas shopping. She said she plans on giving less extravagant gifts to remain within her budget.

The state is scheduled to announce tomorrow a gas cap price that will take effect next Monday. Last week it announced this week's cap would be 8 cents lower. Yesterday, stations began lowering prices, with Costco in Iwilei trimming its price for a gallon of regular to $2.46, according to Honolulugasprices .com.

Hawai'i historically has had the nation's highest gasoline prices. On Sunday night the statewide average was $2.774 for a gallon of regular, according to the AAA's Daily Fuel Gauge report. That compared to the national average of $2.21 a gallon, a 13.6 percent rise in a year.

Hawai'i's cap is the only one in the nation and was enacted by legislators tired of seeing gasoline prices steadily rise while rarely declining the way they do in other states. The law only regulates wholesale prices. Station owners are free to set prices at the pump, though they generally move in the same direction as the wholesale rate.

The gas cap is based on five days of wholesale price data from three Mainland markets. The Advertiser's preliminary calculation of next week's gas cap is based on the first four days of the five-day period.

The Advertiser uses oil market data from Bloomberg News while the state uses figures supplied by the Oil Price Information Service. The different data sources can result in a variation of a few cents.

Hawai'i's diesel prices are also the nation's highest at $3.447 a gallon, or about 28 percent more than a year earlier. The U.S. average diesel price was $2.68, or about 24 percent higher. Diesel prices are not regulated under the Hawai'i gas cap law.

Reach Greg Wiles at gwiles@honoluluadvertiser.com.