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?
blocks take 10 minutes on average, although it's usually a bit faster on average, because the mining power grows and the difficulty adjustments always lagg behind a little bit.
if you count the amount of blocks we still need to fill the next 210,000 blocks and then multiply that by 10 minutes you can get the approximate time with reasonable accuracy, although it's likely that the actual date and time will be a bit sooner than that.