December 5 (30 days after election day) is the final final day for certifying elections in California.  Usually, many California counties have certified before today.  But this year, as a one-time only change responding to some 60,000 ballots left uncounted in 2022 due to signature issues, the state legislature left a longer period for voters to cure those mistakes, effectively precluding certification for most counties until December 3.

Paraphrasing Natalie Adona (who was paraphrasing Doug Chapin, who was paraphrasing any number of election gurus past and future): fast, accurate, cheap: pick any two.