With 6/30/2015 being the last date on which you had an ownership interest in the previous home, 6/30/2017 is the earliest date that you can acquire a new home as a first-home purchaser with regard to the penalty exception. You would want to make the distribution slightly before the closing date, but you cannot make it more than 120 days before the closing date and still qualify for the exception.
If you wanted to push the limits (with almost 100% certainty that you will not qualify as a first-time homebuyer due to the high likelihood of missing the necessary closing date), the distribution could be made tomorrow, 3/6/2017, for a closing between 6/30/2017 (2-years after you last owned a home) and 7/4/2017 (120 days after the 3/6/2017 distribution). However, with regard to a distribution on 3/6/2017, if your closing is originally scheduled for between 6/30/2017 and 7/4/2017 but it becomes apparent that your closing will be delayed beyond 7/4/2017, you have until 7/4/2017 to roll the distribution back into an IRA.
