In one part of the Golden State, prices hit $5.69 a gallon (Â£0.91 per litre), $1.20 more than the California average.
The situation has been magnified by pollution limits requiring a special fuel blend during the summer.
Officials insisted California was not running out of petrol, and one refinery has already resumed production.
The refinery had gone offline because of a power cut, exacerbating the supply problems.
"People may not find gas at a price that they like and there may be some stations where they used to get it that they can't, but our analysis says there is enough gasoline to meet demand," Alison Roberts, a spokeswoman with the California Energy Commission (CEC), told Reuters news agency.
Fuel price spikes particularly affect the state's independent petrol station operators, who pay a higher price for their supplies than some national chains.
Some have closed down their pumps rather than cut into profit margins. Costco, a giant discount store chain that sells large volumes of petrol, closed 14 of its 40 Los Angeles-area stations. Five were expected to reopen on Friday.
As prices increased over the past week, the California Independent Oil Marketers Association requested a waiver from the state's air board requesting to use the so-called winter-blend before the scheduled 1 November switchover.
A spokesman for the California Air Resources Board said there was no timeline for the decision.
Petrol prices are still relatively high around the US, averaging $3.79 a gallon, 39 cents higher than this time last year, according to the American Automobile Association.
But several disruptions have pushed California's average fuel price past Hawaii, which usually has nation's most expensive petrol. As of Friday, the state's average was $4.49 per gallon.
A fire at a Chevron refinery in Richmond on 6 August, one of the region's largest, has left it producing at a reduced capacity.
A pipeline that moves crude to Northern California was also shut down and two plants closed for preventative maintenance.
An Exxon Mobil refinery in Torrance had a power failure, disrupting production for several days, but has since resumed normal operations.
A sharp rise in fuel prices in California linked to state supply shortages has forced some petrol stations to close temporarily.