Metro Phoenix gas prices went up 50 cents a gallon in one month

If you’ve been to a gas pump lately in the Phoenix area, you may have noticed a ballooning price tag. In the last month costs, have jumped more than 50 cents a gallon.

Gas is up in the Valley, topping both the state and national averages at nearly $3.90 a gallon for regular unleaded, according to AAA.

Patrick De Haan with GasBuddy says there are many reasons for the cost spike, including the need for different gasoline blends. The Valley is supplied by California refineries.

“There’s only some areas of Phoenix or Arizona that can use certain types of gasoline," De Haan said. "And when refineries go down, instead of having one large pool of supply, they essentially have to be producing various blends. And this is just Arizona that has five different requirements based on where you are. California also has different times of the year that require these blends.”

De Haan also says one refinery is in the process of shutting down.

"We’ve now started to see the permanent shutdown of a refinery in California that produces just under 10% of California’s entire gasoline supply," De Haan said. "And that again is going to be an issue that hits Phoenix and western Arizona."

Counties like Pima, which gets its gas from a different state, are averaging closer to $3 a gallon. Prices are expected to lower as blends change to the cheaper winter option.