Lots of people will tell you that you can day trade forex 24/5 but I wouldn’t. If you’re after volume and volatility, zero in on the overlaps of the key trading sessions:
London & New York Overlap (1:00 PM – 5:00 PM GMT): Most liquid and volatile period. Good for EUR/USD, USD/CAD, GBP/USD.
Tokyo & London Overlap (8:00 AM – 9:00 AM GMT): Less significant but can still offer opportunities. Good for USD/JPY, GBP/JPY, EUR/JPY.