All right all Start Guessing.
Here is a handy dandy World Clock DooHicky so you don't have to think of all that time zone stuff while making your guess.
Please Post all Guess's in Pacific time zone: UTC/GMT -8 hours.
Reason being is that is were Telltale is at.
My way of thinking is that Telltale wants to get the game to our British Pirates today as promised (Sorry Aussies).
So taking into account for British Summer Time.
(British Summer Time is a strange time warping effect that happens over England. I have looked into it and have come to the conclusion it has something to do with something called a Tardis and a person known as The Doctor. I tried to look into it more but I keep getting this thing saying Tourchwood Classified. There is another theory of what British Summer Time is link to follow.)
I am thinking from 13:00 Standard Time would be about the latest they will release it being that for the British gamers it would be 9 at night and still respectably the 7th.
Now that was thinking the latest they would come out with it today.
The earliest would be 6 AM Standard Time. But it would be more realisitc if it was 9 AM Standard Time. Both of these times work out great for Europe and not just England with their "The Doctor" Summer time thing.
So split the difference and Boom!
My Guess is 7:30 AM Standard Time.