A win in the liberal stronghold that has 415 delegates -- the largest number of any state -- would give the 78-year-old Vermont senator a formidable advantage in the overall race for the Democratic nomination.
Political observers say his appeal in California has only grown since the last presidential election, in large part because he has not wavered on his signature issues, including health care, income inequality and student debt.
He has also aggressively courted Latino voters, who make up about a quarter of the estimated electorate for the California primary.
"Sanders has really focused on engaging the Latino electorate by meeting them where they are, hiring locally and opening field and campaign offices in Latino communities," said Sonja Diaz, founding director of the Latino Policy and Politics Initiative at the University of California, Los Angeles (UCLA).
"It''s pretty clear in terms of his campaign tactics that Latinos are critical to his campaign''s success." Sanders, the oldest candidate in the race, also owes much of his success in California to young voters hungry for change.
"A lot of my peers feel like Bernie speaks to young people''s issues and is really authentic," said Alex Brandolino, 21, a student and vice president of UCLA''s chapter of the California Young Democrats.
"We are a generation that feels like there''s these huge challenges like climate change, health care and student debt, and we need change now to address these issues."
Brandolino feels confident that Sanders will manage to get young voters -- who historically are less likely to turn out -- to actually show up at the polling stations this year in greater numbers.
"I believe that Sanders has developed a real, unique connection with young voters that I think is very rare among politicians, and I do think youth turnout would increase if he is the nominee," he told AFP.
"Whether or not that would offset potential alienation of more moderate and older voters, I don''t know," he added.
Several supporters interviewed at a recent Sanders rally in Santa Ana, south of Los Angeles, said the Vermont senator appealed to them because of his consistent message on key issues and his progressive ideas.
"He''s never changed. Everything he says now, he''s been saying for years and years and years," said Ed Shaiman, 71, a retired teacher. "And I believe he cares about people."
Edgar Pedroza, 25, a bartender whose parents immigrated to the US from Mexico, said he was voting for Sanders because he was convinced he could stand up to President Donald Trump in the November election.
"I just hope that the Democratic Party will rally around Bernie if he is the Democratic nominee," Pedroza said. "Because I think Trump is a horrible human being, and that reflects badly on us as a society, as a country."
Sanders will be going into Super Tuesday -- the most important day on the Democratic primary calendar when more than a dozen states hold primaries -- charged up from his victories in New Hampshire and Nevada and a tie for the lead in Iowa.
He was back in the Golden State on Sunday, telling a rally in San Jose that he was the best placed candidate to beat Trump and urging young supporters to vote.
"This generation does not vote in the kinds of numbers that we need," he told a roaring crowd. "Today I am here to ask you, to beg of you, let us reach out to people all across the state, all across this country... tell them that we need them at our side in the political struggle for justice."
A recent poll by the Public Policy Institute of California showed that 32 percent of likely Democratic primary voters in the staunchly liberal state prefer Sanders.
Trailing well behind in second place is former vice president Joe Biden with 14 per cent, Elizabeth Warren with 13 per cent and Michael Bloomberg at 12 per cent.
The survey showed that among young voters aged 18 to 44 and among Latinos, Sanders enjoys 53 per cent support, far more than the other Democratic presidential hopefuls.
"Bernie Sanders leads all candidates in the Democratic presidential primary today, and he is most likely to be named by voters as the candidate who can win against Donald Trump in November," said Mark Baldassare, president and CEO of the Public Policy Institute.
"He has had a consistent message of a more expansive role of government that resonates with most young adults and Latino voters in California," he added.
"More recently, he has been emphasising the importance of climate change and income inequality, and these are concerns that many Californians are raising about the future of this state." (AFP) MRJ