CoinMarketCap's Altcoin Season Index currently stands at 37, indicating that Bitcoin is outperforming most altcoins. The index compares the price performance of the top 100 cryptocurrencies, excluding stablecoins and wrapped coins, against Bitcoin over the past 90 days. An altcoin season is defined as a period when 75% of top altcoins outperform Bitcoin, but the current score is significantly below that threshold.