Although currencies can be traded 24 hours a day, certain times in the day are better than others.
Whilst the major stock exchanges are open, markets are more active and create more volatility in currency prices. Hence, more trading opportunities are likely to arise.
The main grants are:
Note that the London exchange overlaps with the Tokyo exchange for a period of 1 hour and also overlaps with New York for 3 hours. The Sydney exchange has low influence on the volatility of the markets but is important because it is the first exchange to open on Sunday night and then kicks start the week.
We can therefore expect a high volatility between 8.00 and 9.00 as well as between 13.00 and 17.00
* London time: GMT