Well, the Google June 2021 core update that was announced on June 2nd, began rolling out at 6:30pm ET on June 2nd, but was not really felt much until a few days later is officially done rolling out. It actually took about ten-days to fully roll out and ended on June 12th.
I asked Danny Sullivan about it at the two-week mark on Twitter and he said it is done:
— Danny Sullivan (@dannysullivan) June 15, 2021
I am not sure why Google didn't tell us it was done on June 12th, while they waited until June 15th, but it is what it is.
Normally these rollouts take a full two weeks but this one was special, it took only ten days.
It is interesting that it finished on June 12th because we saw a nice amount of Google fluctuation on June 11th and June 12th - which may be related to the end bits of this core update. It is not for sure related but it can be related. I mean, Google is always releasing new changes to search, but for Google to confirm it finished on June 12th, I am more inclined to say what you saw on June 11th and 12th were related to the last bits of this June core update.
Here is what the month looked like via the tracking tools:
In any event, check your rankings, see if you are up or down after this update. If you are down, do not panic (sorry, had to say that) but we do have a new core update coming in about a month. So hang tight, things may reverse themselves and get better for you - maybe.
Forum discussion at Twitter.