According to the blockchain halving rule, the Bitcoin block mining reward halves every 210,000 blocks, the coin reward will be decreased from 25 to 12.5 coins at 10 Jul 2016 13:24:42,
Can anyone predict what will be the exact time and date for the next halving after this halving?
You can never predict the exact time for the next halving after this one. The blocks are mined at 10 minutes on average, but in reality it's not always 10 minutes. It can be slower and it can be faster. It depends on the miners.
Bitcoin halves every 210000 blocks. So that means the next halving will be 420000 blocks, and the next next one 640000 blocks. That will be on average at around 2020, somewhere near that. When we get closer we can get more accurate with the prediction.