In April, Google updated how the Cumulative Layout Shift (CLS) metric within the core web vitals was calculated. In short, Google made the metric more beneficial to most sites, so your CLS scores may go up by themselves on June 1st in the Google Search Console reports.
On June 1st, Google posted "The CLS metrics have been updated to reflect a more accurate representation of layout shifts on the page. You might see changes in your page CLS statuses (mostly positive) reflecting this change." This is after Google posted on April 13th the same exact message.
But I confirmed with Google that this means that Google noted the change happening in April but the scores themselves were not reflected in Search Console until June 1st.
Jeffery Jose from Google said on Twitter "June 1st changes are reflecting the updated CLS definition as described in the https://web.dev/evolving-cls/ post. It took a few weeks of work to plumb the update through from CrUX to SC."
June 1st changes are reflecting the updated CLS definition as described in the https://t.co/FKr2xiuzhj post. It took a few weeks of work to plumb the update through from CrUX to SC.
— Jeffrey Jose (@jeffjose) June 1, 2021
So you should see improvements to your CLS scores without doing anything.
So check out your core web vitals report in Google Search Console and expect more green bars from the CLS metric:
Update: Here is one extreme example of this making a huge difference for one site:
Google's new CLS metrics are now live in Google Search Console. You might notice some improvements, like the screenshot below. Client has been working hard over the past few months & moved many "poor" to "needs improvement", & now to "good" https://t.co/Wn4RXrrIPA via @rustybrick pic.twitter.com/0enOEE5w1T
— Glenn Gabe (@glenngabe) June 2, 2021
Forum discussion at Twitter.
Update: On June 7th, Google tweaked the wording to read "The CLS metrics have been updated to reflect a more accurate representation of layout shifts on the page. CLS metric now has a maximum session window with 1 second gap, capped at 5 seconds as detailed in the post here. You might see changes in your page CLS statuses (mostly positive) reflecting this change."
