Google’s frequent algorithm changes have been a topic of discussion for many years now, and the rate of change seems to be increasing. In 2021, Google reported a staggering 4,367 “launches,” up from 350-400 in 2009, resulting in nearly a dozen changes per day on average. While many of these changes were likely small, some were major, and understanding them can help us prepare for the future.

Thanks to the MozCast research project, we have daily algorithm flux data going back to 2014, and it reveals some interesting trends. While 2022 was undoubtedly hotter than 2014, the rising temperatures over time are much more complicated than that. In some cases, it’s difficult to map temperatures directly to algorithm updates, and in others, there are known causes outside of Google’s control.

For example, the WHO declaration of the global COVID-19 pandemic in March 2020 changed consumer behavior dramatically and reshaped search rankings along with it. Another example is the summer of 2017, which saw unexplained algorithm flux that lasted for months. One possibility is that Google’s Mobile-first index update caused large shifts in rankings as it was being tested in the year or more preceding the official launch, but it remains speculation.

Interestingly, not all of the hottest days on Google from 2014-2022 were named updates. One of the hottest days on record in MozCast was a major outage in August of 2022 that measured a whopping 124°F. The 8th and 10th hottest confirmed days over these nine years were serious bugs in the Google index that resulted in pages being dropped from the search results.

If we’re talking about named updates, the highest-temperature update was actually a penalty-reversal, phase 2 of the Penguin 4.0 update in October of 2016. Phase 2 removed all previous Penguin penalties, an unprecedented move on Google’s part, and a seismic algorithmic event. If we factor in the 7+ major, named Penguin updates (and possibly dozens of smaller updates and data refreshes), then Penguin is the clear winner among the thousands of changes from 2014-2022.

Looking to the future, Google’s “weather” is driven by human choices, and occasionally, human mistakes. As machine learning drives more of Google search, the signals from Google will likely become less clear, but the themes of the next few years will probably be familiar. Google wants valuable content that reflects expertise, authority, and trust, delivered on sites that are fast, secure, and mobile-friendly. They don’t want sites built purely for SEO or cluttered with junk.

While we can learn from the past and read between the lines of Google’s messaging, predicting future changes is impossible. However, the only guarantee is that search engines and search engine optimization will continue to exist as long as people need to find information, people, places, and things. For a full list of major algorithm updates back to 2003’s “Boston” update, check out the Google algorithm update history.