What Is the Altcoin Season Index?

The Altcoin Season Index measures how widely altcoins are outperforming Bitcoin. It compares the 90-day performance of a group of leading non-BTC assets—typically the top 50 or top 100 by market cap—against Bitcoin.

The index score ranges from zero to one hundred and reflects the percentage of assets in the sample that outperformed BTC during that period.

• A score of 75 or higher signals an Altcoin Season
  
  

• A score of 25 or lower indicates a Bitcoin Season

Stablecoins and wrapped or asset-backed tokens (such as USDT, DAI, WBTC, and stETH) are excluded to avoid skewing results.

Why Traders Watch It

Crypto bull markets often follow a capital rotation cycle:

• Bitcoin leads

• Then Ethereum gains momentum
  
  

• Followed by large-cap and eventually small-cap altcoins
  
  

Key signals:

• A rising index, especially when moving from the mid-fifties toward seventy-five, suggests broadening risk appetite and strengthening altcoin momentum
  
  

• A low index score indicates Bitcoin dominance and altcoin underperformance, prompting shifts toward hedging or early positioning

Reading the Ranges

• 0 to 25: Bitcoin Season – capital concentrated in BTC
  
  

• 26 to 50: Transition – selective strength in altcoins
  
  

• 51 to 75: Altseason Building – rotation gaining traction
  
  

• Above 75: Confirmed Altcoin Season – broad altcoin outperformance, high sentiment, rising volumes

Complement the index with:

• Bitcoin Dominance (BTC.D)
  
  

• Total crypto market cap excluding BTC
  
  

• On-chain activity trends
  
  

• Sentiment indicators like the Fear & Greed Index

How to Use It

• Stage exposure: Add altcoin exposure as the index climbs through fifty and seventy-five; reduce positions if momentum fades
  
  

• Confirm with flows: Look for falling BTC dominance, rising altcoin volumes, and improving funding conditions
  
  

• Adjust by quality: In early stages, focus on majors like Ethereum and Solana; during stronger altseasons, rotate into high-conviction mid- and small-cap tokens
  
  

• Manage risk: If the index spikes and sentiment turns euphoric, consider locking in gains. Be aware that large caps can disproportionately influence index readings
  
  

Key Limitations

• The index is backward-looking—it reflects the past 90 days, not future performance
  
  

• Methodology varies across providers (e.g., top 50 vs top 100)
  
  

• Thinly traded tokens may distort the data
  
  

• A confirmed Altcoin Season does not guarantee gains across all altcoins
  
  

Use this index as a contextual tool—never as a stand-alone signal.