Maybe August 22 is the scheduled date of their first nuclear weapons test. Remember the rhetoric leading up to Pakistans test?
In any case, the rhetoric coming out of Tehran is most probably for local consumption only. Got to be seen to be in control and acting tough in front of the "enemy". These types place a lot of store in that style of leadership.
The leaders of these places spend most of their time looking over their shoulders - and rightfully so, I reckon!