Official Release Date & Time: April 14, 12:00 AM BST
Originalmente postado por Rockstar Games:

Question: When will GTAV be released for PC?

Answer: The PC version of Grand Theft Auto V will be arriving on April 14, 2015 at retail and as a digital download. The Day 1 Title Update (required for play in Story Mode and GTA Online) will be live at 12:00 AM BST (in the US, this is Monday, April 13, at 7:00 PM ET, 4:00 PM PT). Pre-loads for digital downloads are currently available via Rockstar Warehouse and Steam.
Grand Theft Auto V PC Release Date And Time[support.rockstargames.com]

http://www.timeanddate.com/worldclock/converter.html

Timezone Release Time
PST April 13, 04:00 PM
CEST April 14, 01:00 AM
CST April 14, 08:00 AM
GMT April 13, 11:00 PM
JST April 14, 09:00 AM
EDT April 13, 07:00 PM
MDT April 13, 05:00 PM
MSK April 14, 02:00 AM
AEST April 14, 09:00 AM
IST April 14, 04:30 AM