Gas prices up another eight cents over the past two weeks.

FOX's Lisa Lacerra reports:

The national average now $2.18 a gallon, up 41 cents over the past nine weeks:

(Lunberg) "Crude oil prices were a cheap cause of this rise over a period of weeks and the other has been U.S. refiners getting ready to supply summer grade gasoline, seasonally this always adds cost to gasoline."

Analyst Trilby Lunberg with the Lundberg Survey. 

The highest price $2.79 in San Francisco. The lowest in Baton Rouge at a $1.82.

Lisa Lacerra, FOX News.