Arizona gas prices have fallen for the third consecutive week, now to below $4 a gallon on average.
Ongoing oil refinery maintenance in California has kept prices from falling even faster.
Julian Paredes with AAA says cheaper crude oil accounts for the latest dip.
"In Arizona, the most expensive gas is in Maricopa County. They are averaging about $4.13 a gallon. Apache County has the cheapest at $3.68," Paredes said.
Pipeline maintenance has allowed Arizona to delay when it will switch to the more expensive summer blend gas by two weeks. That blend will start in mid-June.