What is the DailyFX Volatility Index:

The DailyFX Volatility Index measures the general level of volatility in the currency market. The index is a composite of the implied volatility in options underlying a basket of currencies. Our basket is equally weighed and composed of some of the most liquid currency pairs in the Foreign exchange market.

In reading this graph, whenever the DailyFX Volatility Index rises, it suggests traders expect the currency market to be more active in the coming days and weeks. Since carry trades underperform when volatility is high (due to the threat of capital losses that may overwhelm carry income), a rise in volatility is unfavorable for the strategy.