While this is difficult to determine with link indexes that don’t publish cache dates, Google Search Console makes it fairly easy.
- Download all the links from as many sites as you can in Google Search Console
- Crawl the links to see which have been removed
- Check Google’s cache to see if they have indexed the pages after the links have been removed
- Record the cache dates to determine the oldest pages that Google has cached with removed links, while still reporting the links as present in Google Webmaster Tools
It seems that about 3 weeks is the magic number. There is a substantial drop off at the 3 week mark where nearly everything that has been cached by Google makes its way into the Google Search Console link data.
It is reasonable to believe at this point that Google Search Console link data should be updated within 3 weeks of indexation. Why does this matter? Well, for link removal teams you can give your clients expectations for updates to appear in their data. We can probably assume similar delays in adding links to Google Search Console as well. Finally, if you are using Google Search Console data, you might want to make sure the data is still valid before using it in your analyses.