The way time zones work also contributes to daily volatility. It's still Sunday night in Europe when it's Monday morning in Australia. European and American sessions are closed at this time. The markets are already open, but volatility remains low. Because there isn't much economic activity on weekends, the market is unlikely to adjust to new conditions. Sunday night is the only time during the trading week when currency pairs regularly gap.
As a result, trading the Forex market on Sunday is not recommended. This is why starting your trading week on Sunday is not advised. According to the market's lack of activity, most traders follow this advice. Monday is also not the best day of the week to trade currency. Monday's first half is sluggish.
European traders wait for economic news and macro data: before they decide to open new orders. As the week begins, traders try to anticipate and adjust to future trends. This is why Monday is the least volatile day of the week.