NA: July 10, 2:00am to July 15, 2:00am (PDT)
The time was announced on twitter a short moment ago.
This will be the final testing phase for what they are calling phase 3.
From my previous experience with mmo game testing what this means is that after this, they will go down for a weekend or two, then come back up for another bout of testing called phase 4, go back down for another weekend and then the following week should be early access.
We're only 7 weeks from launch, and it was hinted that early access might be up to a full week early, if not confirmed already somewhere.
That gives us this week starting Wednesday to finish phase 3. Probably the rest of the month without any access, and then a week or 2 of finalized stress testing for phase 4 before final preps for live servers.
I'm so excited, I really hope in phase 4 they be super nice and let us try arcanist. :>
If you are in beta you can read up on some of the focus planned for this session of testing here.