Average retail gasoline prices in Seattle have fallen 13.4 cents per gallon in the past week, averaging $3.84  per gallon Sunday, compared to the national average decline of  9.6 cents per gallon in the last week to $3.56, according to gasoline price website SeattleGasPrices.com.

Including the change in gas prices in Seattle during the past week, prices Sunday were 3.8 cents per gallon higher than the same day one year ago and are 18.6 cents per gallon lower than a month ago. The national average has decreased 23.1 cents per gallon during the last month and stands 10.2 cents per gallon higher than this day one year ago, according to the website.

“With Hurricane Sandy headed for East Coast, there are a number of uncertainties in regards to the impact at the pump for various fuels,” said GasBuddy.com Senior Petroleum Analyst Patrick DeHaan. “There is very little to look back at history and compare this storm to, and so far, it remains to be seen exactly how gasoline and diesel prices will be impacted. For motorists west of the Mississippi, there may be little change in prices because of the storm, but as you head east, especially in the states to be highly impacted, there may be disruptions at various levels. However, any disruptions in supply may be offset by area-wide shutdowns of business, leading to curtailed demand for fuel. We will certainly be keeping everyone up-to-date on the GasBuddy blog throughout the storm,” DeHaan said.

GasBuddy operates SeattleGasPrices.com and more than 250 similar websites that track gasoline prices at over 140,000 gasoline stations in the United States and Canada.