Average gasoline prices are on the rise nationally and in the Pittsburgh area but are still falling across Pennsylvania, according to reports from price tracking services.

According to GasBuddy, the national average increased 11 cents per gallon in the past week to $3.78, while the average in the Pittsburgh area rose half-a-cent to $3.88.

AAA is reporting the statewide average at about $3.77, down about 4 cents per gallon from last week. Statewide, county averages range from $3.60 in Philadelphia County up to almost $4 in Forest County.

County averages in the Pittsburgh area, according to AAA:

• Allegheny: $3.91

• Armstrong: $3.91

• Beaver: $3.91

• Butler: $3.88

• Washington: $3.89

• Westmoreland: $3.86

According to AAA, tight supply and increased demand are the main reasons for rising prices. Regional differences are stark, with prices on the West Coast hitting $6 a gallon and higher, while Texas and Gulf Coast states have prices below $3 in some areas, spokesperson Andrew Gross said.

“At least six California refineries are undergoing maintenance, and there is limited pipeline supply to the West Coast from locations east of the Rockies,” Gross said.

AAA also noted that prices in the upper Midwest have increased since a refinery fire in Toledo, Ohio, on Sept. 20. The refinery could be down for months.

With the national average increasing for a second straight week, Patrick De Haan, head of petroleum analysis at GasBuddy, also noted the sharp differences in trends between regions.

“Some West Coast states saw prices rise 35 to 55 cents per gallon in the last week as refinery issues continued to impact gasoline supply, which fell to its lowest level in a decade in the region, causing prices to skyrocket. While I’m hopeful there will eventually be relief, prices could go a bit higher before cooling off,” De Haan said. “In addition, OPEC could decide to cut oil production by a million barrels as the global economy slows down, potentially creating a catalyst that could push gas prices up further.”

According to GasBuddy price reports, prices in the Pittsburgh area ranged from $3.37 up to $4.26, a difference of 89 cents per gallon. Statewide, prices ranged from $3.09 up to $4.52, a difference of $1.43 per gallon.

Neighboring areas and their current prices, according to GasBuddy:

• Akron: $3.63, up 1 cent per gallon from last week.

• Cleveland: $3.70, up 7 cents per gallon from last week.

• West Virginia: $3.39, down 3 cents from last week.

The national average price of diesel is down 3 cents from last week, standing at $4.86 per gallon, according to GasBuddy.