...or when it's best to stand on the sidelines.
Sundays: Needless to mention there’s almost no movement as no major bank works on Sundays.
Fridays: Some traders take profits/cut losses on Fridays, others don’t, options expire on Fridays, the NFP (Non-Farm Payrolls) is released on the first Friday of the month… you get the point. Fridays are rather unpredictable for retail forex traders.
Holidays: Banks are closed for holidays. You should also fold shop on holidays. When banks are closed, there is very little volume in the market of the currency pair whose country celebrates the holiday. Obviously, if today is a holiday in Japan, you can safely trade GBP/USD.
News Releases: Unless you’re really really experienced, you’d be better off not trying to trade around news releases. Important economic data releases tend to rattle the forex market and produce huge whipsaws in the exchange rates in a matter of minutes, and frequently in both directions. (By the way, placing tight stop losses definitely doesn’t work in news trading.)