The Altcoin Season Index, a key metric from CoinMarketCap, has dropped to 25 as of November 23, indicating a shift in market dynamics favoring Bitcoin. This marks a significant decline from its peak of 78 on September 20 and a weekly average of 31. The index suggests that only 25 of the top 100 cryptocurrencies by market capitalization have outperformed Bitcoin over the past 90 days, highlighting Bitcoin's growing dominance in the market.