Google began a spam update on September 24. Search Engine Roundtable reports a second phase on Sept 30 to Oct 1 after a first wave on Sept 25-27; the rollout should take about two weeks.
What is happening
Google's Search status dashboard lists the September 2026 spam update as starting on September 24. Beyond the date and category, the dashboard gives no further detail.
Search Engine Roundtable's October 1 article says first effects appeared on September 25-27, then a second wave of volatility was reported from September 30 to October 1. Some site owners reported large traffic drops on September 30, and volatility in Discover was also mentioned.
Background
The same article says Google indicated this rollout takes about two weeks rather than the usual couple of days, with effects in several phases. Rankings and traffic may therefore keep moving into early October.
Spam updates aim to curb practices that lower search quality. The dashboard does not say which practices are targeted this time. The reported effects are individual observations, and no single site can conclude from them alone that the update is the cause.
TAKEAWAY
What this means for your project
While an update is rolling out, do not rewrite pages in a panic if traffic moves. Record the dates and affected pages in Search Console. Also check for mass-produced near-duplicate pages, pages stitched together from other sites' text, and AI-generated text nobody has reviewed. Judge once the rollout ends and you can see whether the change persists.