Dr. Copper and particularly copper/gold has been a powerful economic indicator for market stages and cycles. While having a low correlation with many assets, BTC is not immune to the pressure that copper/gold exert on the markets. BTC had a high correlation at times of peaks:
2013 BTC peaked - Copper/Gold peaked -
2017 BTC peaked - Copper/Gold peaked -
2019 BTC peaked - Copper/Gold peaked -
2021 BTC peaked - Copper/Gold peaked -
BTC can of course move on its own and 2019 might be the best testament of that. However, if BTC is correlated to Copper/Gold, it could be headed down. Copper Gold shows the following currently: