The wholesale price of California gasoline hit a record $4.39 a gallon Thursday, the Los Angeles Times reported.
Many filling stations across the state shut down their pumps as soon as they ran out of fuel they'd bought more cheaply.
A sign at one Costco station read: "We do not know when we will be resupplied."
Analysts attribute the rise in wholesale prices to a number of mishaps at the state's 14 refineries and its pipelines.
"Most recently there has been a problem with an oil pipeline that supplies gasoline for Tesoro, Valero and Shell stations," said Patrick DeHaan, senior petroleum analyst for GasBuddy.com, a price-tracking website.
Tom Kloza, chief oil analyst for the Oil Price Information Service in New Jersey, added there was a sense of panic among wholesale buyers over continuing refinery problems.
"There is a sense out there that this might not just be the typical run of bad timing and bad luck in terms of refinery outages," Kloza said. "People are beginning to wonder whether something else might be involved. Has the heat been a factor? Is the electrical grid holding up? Are these refineries just a little too old?"
Meanwhile, buyers at the pump are shocked to see the high prices at gas stations that are still open.
"Holy shoot! I didn't notice that earlier," Aaron Belcher, 38, said. "This is ridiculous."