After upgrading to El Capitan, I wanted to try the natural language search feature in Spotlight, but for me Spotlight behaves exactly like in Yosemite, it doesn't exhibit any of the new features. For example, no results are coming back for searches like "Weather in Cupertino" or "Documents I've worked on last week". Do I need to enable the new functionality somehow?
To answer my own question, Spotlight suggestions are only available in specific countries: https://www.apple.com/osx/feature-availability/#spotlight-suggestions
Natural Language Search, available for English (UK) on the link you gave, didn't work for me (English, in UK) but "Weather in xyz" did oddly enough.
Once I had re-indexed Spotlight (I used maintenance tasks in the Clean My Mac app I have) all of the Natural Language Searches seem to work ok.