What date does the 2016 halving happen at? When does the 2016 halving happen? Is it a predicted date or could it be when network load is achieved?
The first block with the halved block subsidy is 420,000. However, blocks are discovered in a random process – whereas the protocol aims to have blocks found approximately every ten minutes, in effect blocks are currently found about every 8.94 minutes. Therefore, one can only estimate the precise arrival of the Halving:


thehalvening.com estimates 2016-07-10 – 10:24 UTC  
bitcoinclock.com estimates 2016-07-10 – 05:39 UTC  
bitcoinblockhalf.com estimates 2016-07-10 – 10:10 UTC


It's not clear from the sites whether they rely on the current measured block interval or the theoretical ten minutes for their estimates. So far, it seems to me that the time has mostly been overestimated, earlier predictions were for later in July. 

It seems therefore likely to me that the halving will occur on the 8th, 9th or the 10th of July. Naturally, any predictions will increase in accuracy as the halving draws nearer.