"We're not sure if they're just taking a breath, and then continuing on their way up, which hopefully doesn't happen," said Marie Montgomery of the Auto Club of Southern California.
Montgomery said if it is a peak, it would be unusual for March, but not impossible.
"That would be, of course, great news for drivers if it started going down," she said.
The average price of a gallon of gas in Los Angeles is now $4.39. That's up from $3.87 a month ago, but still shy of the record of $4.63 in June 2008.
Ventura County is also at $4.39, but L.A. is a few fractions of a cent higher. In Orange County and the Inland Empire, the price is just one cent lower at $4.38. Hawaii drivers are paying the most in the nation at $4.44 per gallon.
Across Southern California, prices have jumped nearly a dollar over the past month. Denver has the nation's lowest price at $3.36.
Experts say pump prices are rising on the expectation that supplies will dip next month while refineries switch from winter to summer gasoline blends.
The Associated Press contributed to this report.