Vermont Sen. Sanders, who on Saturday started a series of eight Southern California rallies over four-day period, is favored by 39 percent of likely Democratic primary voters, while former Secretary of State Clinton is preferred by 57 percent. The numbers are virtually identical to a poll by the same group released three weeks ago.

“Pollsters have been wrong about Sanders before, especially in Michigan, but we see little in our research to indicate that Sanders will overtake Clinton in California,” said Jay Leve of SurveyUSA, which conducted the poll. “Nor is there a trend line that suggests that Sanders would catch Clinton in California if only he had more time.”

The latest poll numbers are virtually identical to a SurveyUSA poll three weeks ago. The survey in the Clinton-Sanders matchup polled 803 likely Democratic primary voters, with a margin of error of 3.5 percent.