Google's John Mueller said that with some Google search algorithm updates, it is like when you plant seeds in your garden. In short, he said it is not always easy to define when a search algorithm update launches precisely because you might not see anything sprout immediately after planting the seed.
John wrote on Twitter that it is hard to give an exact date for when the algorithm updates start because it is like planting those seeds. He said, "You plant a seed in your garden. The neighbor wants to know when it starts growing and when it will stop, so that they can take photos. What do you tell them?"
Here is that question and answer on Twitter:
You plant a seed in your garden. The neighbor wants to know when it starts growing and when it will stop, so that they can take photos. What do you tell them?
— John Mueller is mostly not here 🐀 (@JohnMu) January 7, 2023
He gave a similar answer last week on the topic of defining start and end dates for algorithm updates. Then he said it was more about baking bread, he wrote on Mastodon, "It's hard picking a date for some of these (especially afterwards). For many (not all) updates, the update rolls out, it takes a while to be visible (which is when we call it a start), and it takes a while to be in most queries / URLs / datacenters (which is when we call it done). There's no binary border for start / stop, it's more about "starts being visible" and "mostly settled down". It's a bit like timing when bread rises when you bake it."
Forum discussion at Twitter.