My fiance and I are waiting 90 days now for the letter for our interview date at the US consulate in HCM, Vietnam.
Of course we are tired of waiting for the date to come made more frustrating by not being able to get even a scrap of information from the consulate through their web based inquiry system. Only that our case is in the queue...continue to wait.
Some info i have seen here is that someone claims to know that the consulate is running about 100 days for the interviews letters to come. Meaning we have about 10 more days.
Looks like in the past the average was 1 or 2 months. But we surmise that because of the recent scandal and arrest of several US visa officers including the head, that things are going slower there due to more checks and scrutiny and perhaps more trainees on board.