Google is going offline. The key to a lot of Google services has been an active connection to the internet, but with the launch of new Docs and Sheets app which work offline, it appears Google is trying to make their apps more accessible when that internet connection dies, and Google Now is joining the party.
The official Google+ page has announced that as of yesterday, the Google Search app has been updated to allow Google Now cards will stay loaded even without an internet connection. Whether you’re offline due to network problems, or deep in the bowels of a sub-terranean train station, you’ll still have access to your Google Now cards.
Source: Google+.