September was not a good month for the wallets of California drivers.

Statewide, gasoline prices soared to a record premium above the national norm, skyrocketing five times faster than the U.S. increase in a period better known for price cuts.

There’s plenty of blame to go around. Middle East tensions boosted global crude oil prices, a critical fuel component. Trade battles make imports tricky. And California refineries have had some production challenges.

Historically high gas prices are displayed at the Mobil station on Edinger and Main Streets in Santa Ana, CA on Tuesday, October 1, 2019. (Photo by Mindy Schauer, Orange County Register/SCNG)

Historically high gas prices are displayed at the Shell station on North Tustin Avenue and East Fourth Street in Santa Ana, CA on Tuesday, October 1, 2019. (Photo by Mindy Schauer, Orange County Register/SCNG)

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Historically high gas prices are displayed at the Shell station on North Tustin Avenue and East Fourth Street in Santa Ana, CA on Tuesday, October 1, 2019. (Photo by Mindy Schauer, Orange County Register/SCNG)

Historically high gas prices are displayed at the Shell station on North Tustin Avenue and East Fourth Street in Santa Ana, CA on Tuesday, October 1, 2019. (Photo by Mindy Schauer, Orange County Register/SCNG)

The average cost per gallon of gasoline is above $4.00 per gallon. A Chevron gasoline station sign on Canoga Ave. and Roscoe Blvd. in Canoga Park, CA. on Tuesday, October 1, 2019. (Photo by Dean Musgrove, Los Angeles Daily News/SCNG)



The average cost per gallon of gasoline is above $4.00 per gallon. A Chevron gasoline station sign on Canoga Ave. and Roscoe Blvd. in Canoga Park, CA. on Tuesday, October 1, 2019. (Photo by Dean Musgrove, Los Angeles Daily News/SCNG)

The average cost per gallon of gasoline is above $4.00 per gallon. A Mobile gasoline station sign on DeSoto Ave. and Vanowen St. in Woodland Hills, CA. on Tuesday, October 1, 2019. (Photo by Dean Musgrove, Los Angeles Daily News/SCNG)

The average cost per gallon of gasoline is above $4.00 per gallon. A Shell gasoline station sign on Ventura Blvd. and Lindley Ave. in Tarzana, CA. on Tuesday, October 1, 2019. (Photo by Dean Musgrove, Los Angeles Daily News/SCNG)

But no matter the culprit, the state’s usually pricey fuel got an unusually large jolt in September.

My trusty spreadsheet, filled with weekly U.S. Energy Information Agency data, found California’s average retail price for all grades was $4.03 as of Sept. 30 — up 52 cents, or 15%, from Aug. 26.

That’s a much larger jump than what was seen nationally. U.S. pump prices were up 7.6 cents, or 3%, in the month to $2.74 a gallon.

That boost adds up to California drivers paying $1.29 more than the national norm — a 47% premium. It’s the biggest gap between state and national prices, according to agency data dating to 2000.

Seasonal switch

It’s also an odd time of year for price hikes, which is typically a springtime pain. Come fall, refineries are switching from cleaner-burning summertime formulations to the less expensive winter blend.

Since 2000, gas prices have averaged a 6 cent drop in the five weeks through September’s end, with the largest increase — 25 cents in 2004 — merely half this year’s jump.

And it was painful at both ends of the state. Los Angeles gasoline went for $4.06 at September’s end — up 58.3 cents, or 17%, in a month. In San Francisco, gasoline ran $4.08 — up 49.2 cents, or 14%.

California gas is never cheap on a national basis. Forget about limited refining capabilities and air-quality production quirks. The state leads the nation in gasoline taxes.

California drivers pay 62 cents a gallon in state taxes and fees vs. a national average of 36 cents, according to the American Petroleum Institute. So taxes only explain one-fifth of this week’s record-breaking price gap.

And, remember, some analysts suggest there’s roughly 28 cents a gallon worth of unexplained industry costs in the California gasoline production process.

California stands alone

This recent price upswing is mostly a California phenomenon, too.

West Coast gasoline, minus the Golden State, averaged $3.13 at September’s end — up only 8.6 cents, or 3%, in a month. In Seattle, the $3.35 average was up only 0.2 cents a gallon over the month.

If it makes Southern Californians feel any better, Colorado is hit hard, too. Its gasoline rose 9% this month (22 cents) but that pushed pump prices there only to $2.80 a gallon.

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Looking elsewhere, early autumn driving looks affordable.

Texas? At $2.39 a gallon, gas is up 3.1 cents, or 1%, in a month. Florida’s $2.47 is up 7.6 cents, or just 3%.

And pump prices are actually down in several East Coast markets.

Massachusetts’ $2.66 is down 6.1 cents in a month, or 2%. And in New York City, not known for having anything affordable, it’s $2.66-a-gallon average is down 8.8 cents for September or a 3% drop.