The state Public Utilities Commission could announce another cut in Hawai'i's gasoline cap today because of wholesale price declines on the Mainland.

Advertiser calculations show the state will cut the wholesale cap by 3 cents to 4 cents. The new price limit will go into effect on Monday and could result in retail prices falling into the mid-$2.50 a gallon range at O'ahu's lowest-priced stations.

The decline will be the fifth consecutive drop for the cap, which is announced each week. During the past four weeks the cap has been chopped 78 cents.

A new price cap is announced each Wednesday to take effect the following Monday. The cap is based on the average of five days of wholesale prices in New York, the Gulf Coast and Los Angeles. The cap limits what wholesalers can charge and doesn't regulate retail prices at the pump.

Yesterday, Costco in Iwilei was selling regular gasoline at $2.58 a gallon, according to Honolulugasprices.com. The American Automobile Association's Daily Fuel Gauge Report gave the state's average fuel regular price at $2.82 as of Monday night.

That compared with the national average of $2.378, according to AAA. That's 18.8 percent higher than a year earlier; Hawai'i's price is about 17.3 percent higher.

The Advertiser's calculation of next week's price cap is based on market data from Bloomberg News. It can vary from the actual state cap because the PUC uses figures supplied by Oil Price Information Service.

Reach Greg Wiles at gwiles@honoluluadvertiser.com.