Core update is still the main weather system
Google's March 2026 core update is still rolling out on April 7, now on day 11 of what Google said could be a two-week rollout. That matters more than any one-day ranking wobble, because core updates reshuffle how Google judges overall content quality, not just technical settings. Google also says sites should wait until the rollout is finished, then give it about a week more before judging winners and losers in Search Console.
The live SERP data fits that picture. Rankings were extremely hot in mid-March, then cooled from "alarm bells" to "still unstable." The last stretch has been elevated, not calm, and the latest completed day, April 6 at 6.2/10, suggests the storm has eased a bit without actually clearing. Today's partial 6.2/10 should be treated as incomplete, but the broader trend is a slow cooldown with rebounds, which is exactly what a rolling core update often looks like.
Today's fresh Google change is small, but real
Google Search Central quietly logged an April 7 documentation update saying video structured data thumbnail URLs must use supported Google Images file formats. That is not a ranking earthquake, but it is actionable for publishers, ecommerce teams, and anyone relying on video rich results. If thumbnails use odd formats, Google may not handle them the way site owners expect.
This is the kind of detail people miss during update week. Everyone stares at traffic charts, while smaller documentation changes can create avoidable visibility problems.
What site owners should do now
- Do not panic-edit pages just because rankings moved this week.
- Check whether drops started after March 27, 2026, not before.
- Review pages that lost traffic for originality, usefulness, and trust, not keyword density.
- If you use video markup, confirm your thumbnail file format is supported.
- Wait for the rollout to finish before making big conclusions.
Bottom Line
This is a stormy SEO day, but not a mystery. An active core update is still moving through Google's systems, and the volatility trend says the worst heat has cooled, not disappeared. The smart move is calm triage, not reckless surgery.