So when is the actual patch?

Your 1AM EST is their 10PM PST which is when they usually start patches (albeit on Tuesday nights, not Mondays), so that works.

I'm a bit concerned about their being no formal annoucement of the hours yet, but maybe they are waiting until the "End of the World" event to do the "Oh No! Maple World is overrun! We're going downnnnnnnnnnnnnnnn!" thing