Well, sometimes a large-scale earthquake can be predicted on the same day without much equipment - read about 1906 San Francisco quake, when there were rumblings and shakings hours before the 8.3 magnitude disaster.
A good monitoring network of various sensors can usually give you a warning that someplace around there a quake will happen some day around then.
I don't know the figures behind these somes, but apparently there is no method reliable enough so far.
There are also various speculations, ranging from plausibility of sattelite tracking of specific pre-quake dust clouds and all the way down to shamen and clairvoyants.