Frostwyrm Lair will open at the following times per region:
Americas: Tuesday, August 19th at 11:59 PM PDT
Europe: Tuesday, August 19th at 11:59 PM CEST
Korea/Taiwan: Wednesday , August 20th at 12:59 AM KST / Tuesday, August 19th 11:59 PM CST
China: Tuesday, August 19th at 11:59 PM CST
(Americas Region) The cards that players can acquire in Frostwyrm Lair will be featured on the official Hearthstone blog here once Frostwyrm Lair is live in the Americas region.
Good luck and have fun acquiring new cards for your Hearthstone collection!