Andrew Kamsky
Bitcoin’s September Return Edges Above Its 13-Year Median
September 15 to 21 has historically been Bitcoin’s weakest week of the month, with an average decline of 2.19% across 2013 to 2025. Bitcoin fell to about $75,000 by September 16, then recovered to about $80,900 by the September 19 daily observation. That puts BTC up 2.95% from September 1, compared with a historical median gain of 1.81% at the same point in the month. Across the thirteen previous Septembers, that daily median fell from a gain of 1.81% on September 19 to a loss of about 4.5% by September 28, so the coming days remain an important test of this recovery. In short: Bitcoin entered the usual weak period, but has recovered and is currently outperforming September’s historical path. The week is not over yet. Source: Coinjuice’s thirteen year September seasonality study. Data through the September 19, 00:00 UTC observation.