What is CLS by browser timezone
CLS by browser timezone shows Cumulative Layout Shift (CLS) across users grouped by the timezone set in their browser — typically reflecting their geographic location.
This breakdown helps you uncover regional layout stability issues without relying on IP-based location data. It’s especially useful for detecting time zone–linked bugs, content mismatches, or delivery delays that impact layout behavior.
Only timezones with real traffic during the selected period are shown.
This is based on the user’s system clock, not IP geolocation — a privacy-friendly way to understand performance patterns by region.
Time zone can correlate with regional content, CDNs, and user behavior. For example:
Certain time zones may see region-specific ads or popups that shift layout.
Pages might render differently based on language or personalization features tied to time/location.
Late-loading assets from distant servers can cause visible layout shifts.
CLS by browser timezone sample
If CLS is green across most or all timezones, you’re in a good place. Slight differences are normal — but watch for spikes in zones where your traffic is concentrated.
Unhealthy CLS by browser timezone
If a specific timezone shows poor CLS, it could be due to:
Localized content loading late or unpredictably (e.g. language-specific banners).
Third-party scripts behaving differently in certain regions.
Ads or cookies loading conditionally based on local laws or user preferences.
Layout bugs that affect RTL vs LTR language rendering.
This can be especially problematic if the affected timezone represents a key market.
Resolving unhealthy CLS by browser timezone
Go-to action plan to resolve an unhealthy CLS by browser timezone:
Ask Uxi to analyze your CLS by browser timezone values and suggest improvements
Use Filters to zoom in on the affected timezone and see which pages or users are most impacted.
Simulate CLS of the suspected breakdown to see if fixing it will resolve the CLS by browser timezone. If yes, this is where the resolution focus should be.
Use an automated CLS optimization tool like Navigation AI to improve your CLS by browser timezone values
Once you’ve improved CLS, set an alert to be the first to know if it starts worsening again.
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