The question of volume in the forex market is a common one seeing as there is no one central aggregation of the data. I happen to work for a company that has a major forex dealing platform in it, so I get to see some stuff that isn’t available to the public. One of those things is how volume is distributed throughout the day.
Here’s a graph of EUR/USD volume based on Thursday’s trading (times noted are in GMT).
The pattern is pretty obvious. The volume in the Europe/US overlap is the most significant. Outside of that it’s markedly lower.
And to provide a perspective on a currency that would be thought to have a more regional bias, here’s AUD/USD.
Here we see more of an Asian time frame volume spike, but still we have to look at the US morning as the biggest volume period.
Of course this is just one day – a day when there were important data releases in both the US and European mornings, which is reflected in the spikes we see in EUR/USD. Other days will show different distributions. The primary pattern of heaviest volume in the overlap will basically always be there, though.