The Altcoin Season Index has fallen to 16 as of December 28, indicating a significant decline from its peak of 78 on September 20. This index, which measures the performance of the top 100 cryptocurrencies against Bitcoin over the past 90 days, suggests that fewer altcoins are outperforming Bitcoin. The data, sourced from CoinMarketCap and reported by Chainthink, highlights a cautious sentiment in the market, further emphasized by the persistent caution signaled by the fear and greed index.