California's governor's race is tightening as many Democratic voters appear to be waiting until the final hours to cast their ballots.

Ballot-tracking data shows Democrats are voting at a slower pace heading into Election Day, fueling expectations of a late "blue surge" that could shift the final outcome once all ballots are counted.

Democratic strategist Steve Maviglio says the trend reflects voters who are still weighing their choices.

"To me, it's voters hanging onto their ballots until the bitter end," Maviglio said.

Data from Political Data, Inc. show a slow increase in ballots cast on Monday, with registered Democratic ballots cast still trailing registered Republicans 18% to 21%, respectively.

The latest Emerson College poll shows Democratic candidate Xavier Becerra leading the field with 28% support, followed by fellow Democrat Tom Steyer at 22%. Republican Steve Hilton sits at 21%, while Republican Chad Bianco has 12% support.

With the race still tight, Hilton is now making a last-minute call for Bianco to drop out of the race in an effort to consolidate Republican support and improve the party's chances of advancing to the November general election.

"For Republicans who have not voted yet, and still intend to, they really should be focusing on making sure they have a candidate in the runoff," Republican strategist Rob Stutzman said.

Meanwhile, Democratic campaigns have also ramped up attacks in the final stretch of the primary.

Steyer recently launched an attack ad targeting Becerra, linking him to a corruption case involving his former chief of staff.

Becerra's campaign fired back with a cease-and-desist letter to take the ads down, calling them "false and defamatory."

With thousands of ballots still outstanding, strategists say the governor's race remains too close to call and could take days or even weeks to fully resolve.