Alt Season Index
How many of the top 50 altcoins beat Bitcoin over 90 days · source: Binance, CoinGecko
Alt Season Index
data as of 10/15/2026 · Related: KM Cycle Index · Dominance and market cap · ETH/BTC ratio
Altcoin performance against Bitcoin over 90 days
The measurement covers the largest altcoins by market cap that have a USDT pair on Binance. Stablecoins and tokenised commodities are excluded — their price tracks the dollar or gold, so they would only dilute the result. A coin without a pair is left out entirely, which is why slightly fewer than fifty are usually measured.
How to read alt season
In a cycle the market moves in order: Bitcoin first, then the large altcoins, and the small ones last. The Alt Season Index measures that rotation in the simplest possible way — it counts what share of the fifty largest altcoins beat Bitcoin over ninety days. Above three quarters people speak of alt season; below a quarter, of bitcoin season.
Ninety days is not arbitrary. A shorter window would present every weekly swing as a change of trend; a longer one would catch the rotation only once it was over. Even so, a single reading is not a trend — what matters is whether the index climbs or falls for several weeks in a row.
The index is read alongside Bitcoin dominance, which sits next to it. Falling dominance in a rising market is the same thing seen from the other side: capital is not leaving the market, it is moving out of Bitcoin. But when both fall together with the price, it is not alt season — it is money leaving altogether.
Performance is computed from Binance closing prices, the coin ranking comes from CoinGecko. This is not investment advice.