Definition. The highest and lowest Bitcoin price recorded over a rolling 30-day window, drawn as an envelope around spot price, together with the width of that envelope expressed as a percentage of its lower bound.

Technical. Price is sampled at hourly resolution. The upper bound is the rolling maximum of the hourly high over the trailing 720 bars and the lower bound the rolling minimum of the hourly low over the same window, so the envelope reflects true intraday extremes including wicks rather than closing prices alone. The column series on the lower axis is the high less the low divided by the low, so a reading of 20% means the high sits 20% above the low, not that price is 20% from either bound. The horizontal marker repeats the most recent value of that series across the chart as a reference level.

Interpretation. Each bound is flat wherever the extreme of the past 30 days is older than the current bar and steps only when a new extreme prints, so the length of a flat stretch measures how long an extreme has stood. Price resting on the upper bound means a fresh 30-day high is being set, and on the lower bound a fresh 30-day low. Range width contracts when trade is confined to a narrow band and expands after a directional move or a volatility event, which makes the column series a coarse realised-volatility proxy over the same window. Because the window is four times longer the bounds step less often and the flat stretches are correspondingly longer, capturing the full swing of an intermediate move rather than a single week of noise. A 30-day range that has compressed towards its 7-day counterpart indicates that the month's travel has been concentrated in the most recent week.

Notes. The counterpart over a 7-day window is shown in 7-day Price High and Low; the two are read together to distinguish a brief compression in range from a sustained one. For fixed rather than rolling reference levels across the current cycle, see Fibonacci Retracement.