CoinMarketCap's Altcoin Season Index currently reads 45, a metric that measures whether Bitcoin or alternative coins are winning on price over a rolling 90-day window. At this level, the index signals Bitcoin season: the leading cryptocurrency is outpacing most altcoins, not the other way around.
The index works by tracking price performance of the top 50 cryptocurrencies by market cap, excluding Bitcoin and Ethereum. When the reading climbs above 50, altcoins are gaining relative ground. Below 50, Bitcoin pulls ahead. A reading of 45 sits firmly in Bitcoin's favor.
This stall matters because it reflects what traders already see in markets. Bitcoin has held the #1 spot by market capitalization while most layer-one protocols and smaller assets have treaded water. Infrastructure projects, in particular, often lag during Bitcoin-heavy cycles because capital clusters around the safest narrative rather than spreading across development bets.
The 90-day window means the index captures medium-term momentum, not daily noise. A sustained reading in the low 40s would imply Bitcoin strength has real staying power, not just a flash move. If the index climbs back toward 60 or higher, it would signal builders and traders rotating back into protocol upgrades, validator economics, or new infrastructure plays. For now, it hasn't.
Protocol teams watching their token price decline relative to Bitcoin often cite broader market conditions. The index offers a cleaner picture: it's not that altcoins crashed, but that Bitcoin outran them. That's a narrative difference that shapes developer morale and fundraising appetite differently than a pure bear market would.