The US trading hours, roughly 8 a.m. to 5 p.m. Eastern, where most US economic data and equity-driven flows hit forex.
The four forex trading sessions. Currencies trade around the clock because the big financial centres open one after another. London and New York are both open between 12:00 and 16:00 UTC, which is the busiest stretch of the day.
The morning overlap with the london-session is the busiest period. nfp, cpi, and fomc announcements all land during New York hours, producing the largest moves of the month.
After London closes at noon Eastern, liquidity thins and ranges narrow into the 5 p.m. rollover.
Example: an FOMC statement at 2:00 p.m. Eastern can move EUR/USD 80 pips in minutes, during the quieter part of the New York session.