How much time does it take the update of statistics from Search Console?

Almost one month.

 

I did an experiment. Having some pages on a well indexed domain with multiple daily visits from GoogleBot.

 

Initially with a red CLS so the pages were "poor URL", let it stabilize, then modified the pages to orange CLS so the pages went to "URLs need improvement"

 

Update done on 27.04.2021 was visible in Search Console on 17-18.05.2021. I don't think it is about a delayed reporting (the update is reported as it was made on 17-18.05.2021) but more likely is the time needed for Google systems to "accept" and process the update.

 

However the reaction time of Search Console in the case of an issue is around one day until it sends the notification.