The AUD is the weakest performing major currency this year
Against the dollar, the aussie has fallen by 3.4% so far this year. And the main reason for that is the indecisiveness of the RBA. While you can't fault the central bank for that considering the position they are in, it leaves little wonder why the aussie is in such a bad spot at the moment.
I highlighted here that to trade the AUD, is also to trade on when the RBA will move. Basically, it is to trade on those expectations.
At the start of last year, the market had some slight optimism that we could see the RBA move possibly in Q3 or Q4 this year. That has since been pushed back to Q1 2019, and the decline in the six-month implied forwards above highlights that.
So as long as the RBA stays indecisive about when it believes a change in the cash rate will come, those expectations are going to get pushed further back and at the same time, the aussie will continue to suffer as a result.