This is a complicated question because there are factors that change how much will be created by PoW even though there is a defined limit. In code, there are 21,000 blocks that will be created during the PoW phase. That works out to 21.875 days ((21,000 blocks * 1.5 minutes) / 60 minutes / 24 hours), or just over 3 weeks.

However once staking has started up, it will happen concurrently to PoW block generation, so the number of blocks created solely by PoW should be reduced, likely by about 25%. See this thread:

https://bitcointalk.org/index.php?topic=600706.msg6882510#msg6882510

So we are likely looking at around 2 weeks until PoW phase is complete.