Google announced the December 2020 core update on 3rd Dec: "Later today, we are releasing a broad core algorithm update, as we do several times per year. It is called the December 2020 Core Update."
Rollout began around 1pm ET. It was the third core update of 2020 and came seven months after the May 2020 core update.
That was a much longer gap than usual. So sites hit in May had waited half a year for a chance to see movement.
The timing drew criticism. Search Engine Land's 2020 year in review called it controversial.
It arrived after Black Friday and Cyber Monday but before the year-end holidays. The review noted the SEO community's frustration with the scheduling.
It was also big. In Search Engine Land's data-provider roundup, RankRanger saw "even more changes than the May update in some areas, especially in the top three results".
Semrush's sensor scored it 9.4. Health, real estate, travel, finance, law and government were among the most affected sectors.
Google confirmed the rollout was complete on 16th Dec, about 13 days after it began.
If your site moved in that window, review the losing pages against Google's core updates documentation and its self-assessment guidance. Our recovery guide covers what recovery typically looks like.
