Even though local exchanges on high streets may have their own working hours, currencies are traded electronically on the international markets 24 hours a day, 5 days a week. This causes fluctuations in exchange rates throughout the day and during the night.
Currency markets exist in 3 major regions: Europe, the Americas, and Asia. The markets across these regions are interlinked (i.e., the same exchange rates apply in every market at all times) and each market's hours are dictated by local working hours. The European market hours follow London working hours, the American markets follow New York working hours, and the market in Asia follows Tokyo and Sydney working hours.
The working hours of each major market are listed below in GMT. These hours apply Monday through Friday.
International currency markets are primarily for investors and banks. To learn how to invest in the international currency markets, click on the link "Become a forex investor" on this page.