Each year, Google changes its search algorithm around 500–600 times. While most of these changes are minor, Google occasionally rolls out a "major" algorithmic update (such as Google Panda and Google Penguin) that affects search results in significant ways.
For search marketers, knowing the dates of these Google updates can help explain changes in rankings and organic website traffic and ultimately improve search engine optimization. Below, we’ve listed the major algorithmic changes that have had the biggest impact on search.
Google Search ranking updates
January 2020 Core Update — January 13, 2020
Google rolled another core update, with MozCast showing heavy flux across three days and a high temperature of 97°F, in line with the previous three core updates (but smaller than the August 2018 "Medic" core update).
BERT Update — October 22, 2019
Google upgraded their algorithm and underlying hardware to support the BERT natural language processing (NLP) model. BERT helps Google better interpret natural language searches and understand context.
September 2019 Core Update — September 24, 2019
Google rolled out another core update. The update measured at 97°F on MozCast (fairly high, but not historically high) and seemed to impact sites affected by previous core updates. Google did not provide many details.
Site Diversity Update — June 6, 2019
Google Search ranking updates
2022 Updates
Data Center Outage — August 9, 2022
An accident at a Google data center in Council Bluffs, Iowa may have resulted in massive ranking fluctuations, with MozCast hitting a historical high of 123.6°F. In some cases, searchers could not access results at all. Search results appeared to normalize the next day.
May 2022 Core Update — May 25, 2022
On May 25th, Google announced the rollout of a core update. The rollout lasted roughly 2 weeks and was completed on June 9th. MozCast recorded peak ranking flux at 103.0°F on May 25th, the first day of the rollout. As with most Core Updates, Google did not provide specifics.
March 2022 Product Reviews Update — March 23, 2022
Google confirmed a significant product reviews update and changed the naming convention to match the Core Updates. The update officially took 19 days to roll out, starting on March 23rd, and built on previous product review updates to identify high quality product reviews.
Page Experience Update (Desktop) — February 22, 2022
Google announced that the Page Experience Update previously released on mobile SERPs would be rolled out to desktop. This rollout officially occurred from February 22nd to March 3rd. MozCast peaked at 99.4°F on March 3rd and 98.8°F on February 23rd.
Google announced that the Page Experience Update previously released on mobile SERPs would be rolled out to desktop. This rollout officially occurred from February 22nd to March 3rd. MozCast peaked at 99.4°F on March 3rd and 98.8°F on February 23rd.
2021 Updates
Top Stories Redesign — December 6, 2021
While not a traditional algorithm update, Google released a major overhaul to the design of Top Stories, splitting it into two columns on desktop and (in many cases) dramatically increasing the amount of SERP real estate occupied by news results.
Product Reviews Update — December 1, 2021
On December 1, Google announced another update to reward high-quality product reviews (and a refresh of the April 2021 update). This update reportedly rolled out over three weeks, and MozCast recorded multiple days of high SERP volatility in December.
November 2021 Core Update — November 17, 2021
On November 17, Google announced the rollout of a core update. While this update officially wrapped up at the end of November, most tracking sites showed a strong single-day spike (with MozCast hitting 101.7°F on November 17). The overlap with Black Friday sparked controversy in the SEO community.
November 2021 Spam Update — November 3, 2021
Google announced another broad spam update, which rolled out over about 8 days. MozCast peaked at 96.9°F on November 2nd. Unlike the July update, Google did not specifically call this a "link spam" update and did not provide much detail about the sites and tactics targeted.
Page Title Rewrites — August 16, 2021
Starting around August 16, SEOs began to notice a substantial increase in Google rewriting page titles in SERPs. Google later confirmed this change (but not the exact date), and, after many complaints about result quality issues, scaled back some of the changes in September.
July 2021 Link Spam Update — July 28, 2021
Google announced a link spam update that reportedly rolled out over 2-4 weeks. According to Google, this was a broad algorithm update across multiple languages. MozCast showed heavy flux on July 28, spiking at 100.3°F.
July 2021 Core Update — July 1, 2021
A follow-up to the June Core Update, the July 2021 Core Update rolled out from July 1-12. Peak volatility on MozCast hit 102.7°F on July 1st, but we saw temperatures in the 90s on July 5th, 8th, and 11th. Like most Core Updates, Google was light on specifics.
A follow-up to the June Core Update, the July 2021 Core Update rolled out from July 1-12. Peak volatility on MozCast hit 102.7°F on July 1st, but we saw temperatures in the 90s on July 5th, 8th, and 11th. Like most Core Updates, Google was light on specifics.
Page Experience Update — June 25, 2021
After multiple delays, Google started rolling out the Page Experience Update on June 25th, announcing that the rollout would continue through August 2021. This update included Core Web Vitals and impacted both organic results and News results (including Top Stories).
Spam Updates — June 23, 2021
Google released two spam updates, on June 23rd and June 28th. It was unclear how the two updates were connected or what specifically was impacted. While specific sites showed significant impacts, there was no clear impact on overall rankings volatility.
June 2021 Core Update — June 2, 2021
In an unprecedented move, Google simultaneously announced the (apparently connected) June and July 2021 Core Updates. The June Core Update reportedly rolled out from June 2-12, peaking in MozCast at a temperature of 107.3°F on June 3rd.
Product Reviews Update — April 8, 2021
Google announced an update to reward in-depth reviews over thin reviews and spammy affiliates (impacting English-language only at launch). While the update seemed focused on review quality, the exact factors involved appear to be complex.
Passage Indexing (US/English) — February 10, 2021
Google rolled out so-called "passage indexing" (which is probably closer to passage ranking) for US/English queries. While we measured two days of moderate rankings flux, it was unclear exactly how the update impacted SERPs. Google initially estimated this update would impact 7% of queries.
2020 Updates
December 2020 Core Update — December 3, 2020
Google announced a Core Update that appeared to roll out quickly, with the bulk of the impact hitting on December 3rd. MozCast hit 112°F, on par with the March 2020 Core Update and August 2018 "Medic" Update. Some sites reported reversals a few days later, but this seems to have been limited.
Indexing Bug, Pt. 2 — October 12, 2020
Google claimed that the bulk of the indexing and canonicalization bug(s) had been fixed by around October 14th. MozCast measured a drop in indexed pages and a temperature of 104°F around October 12th, with temperatures in the 90s lasting for a few days after.
Indexing Bug, Pt. 1 — September 29, 2020
Google confirmed an indexing and canonicalization bug starting in early September. MozCast measured temperatures of 99°F on September 29th and 30th, and detected dips in indexed pages on September 23rd and 29th.
Google Glitch — August 10, 2020
SEOs reported massive ranking changes for a few hours on August 10, which then seemed to disappear. Google later confirmed a glitch in their indexing systems. MozCast registered 97°F the following day (August 11), but it's unclear if this event was related.
May 2020 Core Update — May 4, 2020
Google announced another Core Update (the second of 2020), which caused heavy rankings flux from about May 4-6. Peaking at 113°, it measured on MozCast as the second-highest Core Update after the August 2018 "Medic" update.
Featured Snippet De-duping — January 22, 2020
Google announced that URLs in Featured Snippets would no longer be appearing as traditional organic results, in line with Google's philosophy that a Featured Snippet is a promoted organic result. This had significant implications for rank-tracking and organic CTR.
Google announced that URLs in Featured Snippets would no longer be appearing as traditional organic results, in line with Google's philosophy that a Featured Snippet is a promoted organic result. This had significant implications for rank-tracking and organic CTR.
January 2020 Core Update — January 13, 2020
Google rolled another core update, with MozCast showing heavy flux across three days and a high temperature of 97°F, in line with the previous three core updates (but smaller than the August 2018 "Medic" core update).
2019 Updates
International BERT Roll-out — December 9, 2019
Google confirmed that the BERT natural language processing algorithm was rolling out internationally, in 70 languages. This announcement came after speculation from the SEO community, and the exact timing of the roll-out is unclear.
Google confirmed that the BERT natural language processing algorithm was rolling out internationally, in 70 languages. This announcement came after speculation from the SEO community, and the exact timing of the roll-out is unclear.
BERT Update — October 22, 2019
Google upgraded their algorithm and underlying hardware to support the BERT natural language processing (NLP) model. BERT helps Google better interpret natural language searches and understand context.
September 2019 Core Update — September 24, 2019
Google rolled out another core update. The update measured at 97°F on MozCast (fairly high, but not historically high) and seemed to impact sites affected by previous core updates. Google did not provide many details.
Site Diversity Update — June 6, 2019
Google pre-announced a "site diversity" update, claiming it would improve situations where sites had more than two organic listings. Moz data showed that, while the update did marginally improve SERPs with 3-5 duplicate sites on page one, the impact was relatively small.
June 2019 Core Update — June 3, 2019
Google pre-announced a "core" update, but with limited details. Sites impacted in previous core updates seem to have been affected, in some cases, and some major UK publishers reported heavy losses. On average, the impact was smaller than the August "Medic" update, as measured by MozCast.
Indexing Bugs — May 23, 2019
Two days in a row, Google confirmed indexing bugs. The first bug reportedly was preventing new content from being properly indexed. MozCast confirmed unusually high SERP flux from May 23-25 (peaking on the 23rd), but it's unclear if this was directly related to the bugs.
Deindexing Bug — April 5, 2019
Google confirmed a bug that dropped pages from the search index around the weekend of April 5th. Moz data suggested drops on April 5th and 7th, with about 4% of stable URLs falling off of page one. Most sites recovered soon after.
March 2019 Core Update — March 12, 2019
Google confirmed a "core" update, stating it was the third major core update since they began using that label. MozCast hit a peak of 101.2°F, a bit below March 1st temperatures. No specific details were given about the nature of the update.
2018 Updates
"Medic" Core Update — August 1, 2018
Google confirmed a "broad core algorithm update," with wide reports of massive impact. It rolled out over the period of about a week, but peaked on August 1-2. This update seemed to disproportionately affect sites in the health and wellness vertical, although large-scale impact was seen in all verticals.
Chrome Security Warnings (Full Site) — July 24, 2018
After warning users of unsecured (non-HTTPS) forms months earlier, Chrome 68 began marking all non-HTTPS sites as "not secure." The changes rolled out on July 24, but rely on users installing the latest Chrome version, which can take weeks or months.
Mobile Speed Update — July 9, 2018
Six months after announcing it, Google rolled out the mobile page speed update, making page speed a ranking factor for mobile results. Google claimed that this only affected the slowest mobile sites, and there was no evidence of major mobile rankings shifts.
Video Carousels — June 14, 2018
Google moved videos from organic-like results with thumbnails into a dedicated video carousel, causing a shake-up in results that were previously tracked as organic. At the same time, the number of SERPs with videos increased significantly (+60% in MozCast).
Snippet Length Drop — May 13, 2018
After testing longer display snippets of up to 300+ characters for a few months, Google rolled back most snippets to the former limit (about 150-160 characters).
Unnamed Core Update — April 17, 2018
MozCast picked up heavy algorithm flux that peaked on April 17 and continued for over a week. Google later confirmed a "core" update, but didn't provide any specifics and the update wasn't named by Google or the SEO community.
Mobile-First Index Roll-out — March 26, 2018
Google announced that the mobile-first index was finally "rolling out." Since the index has been in testing for many months, and Google has suggested they are migrating sites gradually, it's unclear how much impact this specific roll-out had on the overall index. Webmaster should begin to see notifications within Google Search Console.
Chrome Security Warnings (Full Site) — July 24, 2018
After warning users of unsecured (non-HTTPS) forms months earlier, Chrome 68 began marking all non-HTTPS sites as "not secure." The changes rolled out on July 24, but rely on users installing the latest Chrome version, which can take weeks or months.
Mobile Speed Update — July 9, 2018
Six months after announcing it, Google rolled out the mobile page speed update, making page speed a ranking factor for mobile results. Google claimed that this only affected the slowest mobile sites, and there was no evidence of major mobile rankings shifts.
Video Carousels — June 14, 2018
Google moved videos from organic-like results with thumbnails into a dedicated video carousel, causing a shake-up in results that were previously tracked as organic. At the same time, the number of SERPs with videos increased significantly (+60% in MozCast).
Snippet Length Drop — May 13, 2018
After testing longer display snippets of up to 300+ characters for a few months, Google rolled back most snippets to the former limit (about 150-160 characters).
Unnamed Core Update — April 17, 2018
MozCast picked up heavy algorithm flux that peaked on April 17 and continued for over a week. Google later confirmed a "core" update, but didn't provide any specifics and the update wasn't named by Google or the SEO community.
Mobile-First Index Roll-out — March 26, 2018
Google announced that the mobile-first index was finally "rolling out." Since the index has been in testing for many months, and Google has suggested they are migrating sites gradually, it's unclear how much impact this specific roll-out had on the overall index. Webmaster should begin to see notifications within Google Search Console.
Zero-result SERP Test — March 14, 2018
On a small set of Knowledge Cards, including some time/date queries and unit conversion calculators, Google started displaying zero organic results and a "Show all results" button. A week later, Google stopped this test, but we believe it is an important sign of things to come.
"Brackets" Core Update — March 8, 2018
Google confirmed a "core" update on March 7th, but volatility spiked as early as March 4th, with a second spike on March 8th, and continued for almost two weeks. This may have been multiple updates or one prolonged, rolling update. The "Brackets" name was coined by Glenn Gabe; no details were provided by Google.
2017 Updates
Snippet Length Increase — November 30, 2017
After testing longer search snippets for over two years, Google increased them across a large number of results. This led us to adopt a new Meta Description limit -- up to 300 characters from the previous 155 (almost doubling). Google confirmed an update to how snippets are handled, but didn't provide details.
After testing longer search snippets for over two years, Google increased them across a large number of results. This led us to adopt a new Meta Description limit -- up to 300 characters from the previous 155 (almost doubling). Google confirmed an update to how snippets are handled, but didn't provide details.
Chrome HTTPS Warnings — October 17, 2017
With the launch of Chrome 62, Google started warning visitors to sites with unsecured forms. While not an algorithm update, this was an important step in Google's push toward HTTPS and may have a material impact on site traffic.
Google Jobs — June 20, 2017
Google officially launched their jobs portal, including a stand-alone 3-pack of job listings in search results. These results drew data from almost all of the major providers, including LinkedIn, Monster, Glassdoor, and CareerBuilder.
Unnamed Major Update — February 6, 2017
Algorithm changes beginning on February 1st continued for a full week, peaking around February 6th (some reported the 7th). Webmaster chatter and industry case studies suggest these were separate events.
Intrusive Interstitial Penalty — January 10, 2017
Google started rolling out a penalty to punish aggressive interstitials and pop-ups that might damage the mobile user experience. Google also provided a rare warning of this update five months in advance. MozCast showed high temperatures from January 10-11, but many SEOs reported minimal impact on sites that should have been affected.
