Weekend are the most volatile days to trade the best time both to make profit and to lose. Except for those trading less volatile coin but for Bitcoin pairs it's only for the experienced as volatility could be deceptive atimes and same way retracement candles can stand very long making a confusing analysis if the trend isn't well analyzed
Although there's no way to figure out which day is the most volatile day to trade. From the experience, it's really likely that during weekends, we may have come to see the bloodiest days of the week.
It can be like that if we're going to compare the whole week, weekends and weekdays. But in reality, it varies and changing and we don't know if there's really a certainty for it.