That's the highest AVERAGE ROLLING 30 DAY volatility. For example, on Dec 7, 2013, volatility between the high and the low was 54.6%. [1] However, it was lower

That's the highest AVERAGE ROLLING 30 DAY volatility. For example, on Dec 7, 2013, volatility between the high and the low was 54.6%. [1] However, it was lower for the other days of all 30 day periods that include that day, and averaged out to under 15%. 1 - https://www.coindesk.com/price/ https://www.coindesk.com/price/