The Aussie dollar has strengthened significantly against its US counterpart this year, catching almost everyone off guard. 
It's back at the $US0.77 mark, in striking distance of a nine month high. Which is terrible news for our exporters! Wonderful news people for wanting to travel overseas! And so forth.  
But it's important to note that the recent Aussie dollar strength - coming at a time when the local economy does not look that great - is actually really more a story of US dollar weakness.  
Almost every major currency has firmed against the US dollar in 2016 as the interest rate outlook in the world's biggest economy has shifted dramatically. The US Federal Reserve has signalled in recent weeks that it is far less willing to raise interest rates than it was not that long ago. 
As analysts from RBC Capital Markets put it in a recent note, the move higher in the Aussie dollar is "almost entirely accounted for by general US dollar weakness and the Australian dollar is a middle of the pack performer" among major currencies this year. 
The biggest gainers in the currency markets this year have been emerging market currencies in commodity producing nations, such as the Brazilian real and the Russian ruble. That's best explained by the fact that commodity prices have actually staged a surprise rebound in recent weeks.  
The Japanese yen has also strengthened significantly against the $US - that is being driven by a range of factors including safe-haven flows (for various reasons, this tends to happen when people are worried) and concerns the Bank of Japan has run out of options. 
The only major developed economy currency that has weakened against the greenback this year is pound Sterling. And all it took for that to happen was the perfect storm of a looming referendum that could realistically see the UK abandon its 40-year relationship with the European Union. 
All of which is to say, recent moves in the little Aussie battler are a good reminder that we are a small boat being pushed around by some pretty big waves.