Crypto Market Seasonality: Do Calendar Effects Survive a Real Backtest?
"Sell in May." "Uptober." "Sunday dumps." Crypto Twitter repeats calendar folklore every year like it's settled science, but almost nobody who shares these claims has actually tested them against multi-year OHLCV data with a defined hypothesis and an out-of-sample split. Most of what passes for seasonality analysis is a chart screenshot from one specific year, stretched into a rule.