The commonly told sequence runs capital into bitcoin first, then into large alternatives, then into small caps as risk appetite peaks. Practically, altseason is defined by falling bitcoin-dominance alongside a rising total market, since dominance can also fall in a crash when bitcoin simply falls less.
Indices exist that declare an altseason when most of the top 50 coins outperform bitcoin over 90 days. They describe what already happened. By the time one triggers, the move is usually well advanced.
The unflattering statistics are the important part: most alternative coins from any given cycle do not recover their previous highs in the next one, and survivorship makes the past look kinder than it was. Broad outperformance is a phase of a risk cycle, not a category of asset that goes up.
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