Sep 19
27
In 2008 Google added a feature to Google Webmaster Tools (as it was known back then, now known as Google Search Console) to let you set your crawl rate. Google does this automatically based on what your server can handle but you can override it. If you do the override, it can take up to a day for Google to switch to that new setting.
See more here:
Google: The Crawl Rate Setting Takes A Day To Kick In