In March 2009, he predicted the Singapore economy will contract 10% in 2009[Link]
The other thing I remember him predicting was UBS being a good long term investment. He predicted in 2007 that we were in a golden period. In 2008, he predicted that it would take 3-5 years for the world economy to recover[Link]. Before the recent recession he predicted that Singapore will be able to escape a recession because of growth in China and India:
I remember MM Lee once predicted that if the Hong Kongers were to leave en masse because they didn't like the authoritarian Chinese govt after the handover, the Hong Kong economy can keep going with imported foreigners. That one about foreigners he got right but on the wrong island.
Given his track record for predictions, I think I better start preparing for a second dip of this economy next year. I think the stimulus induced growth is too good to be true and when the stimulus runs out, many govts simply cannot keep borrowing to push the economy along.