Let's talk about softs, shall we?
This week you will see the best chance of it, however it all depends on Gringotts. If that's a no-go, the whole area is a no-go. The vacation package people live by those same rules. Either way, I recommend not waiting in front of the Diagon barrier gates, but instead enjoy a nice, cold Duff under the shade at Duff Gardens. If you see movement, make your trek that way.