Timing the crypto market can be as elusive as capturing lightning in a bottle. One day, Bitcoin dominates headlines; the next, altcoins surge into the spotlight. To help investors navigate these shifts, CoinMarketCap (CMC) introduced the Altcoin Season Index—a data-driven tool that clarifies whether the market favors Bitcoin or altcoins. This guide explores how the index works, its implications, and strategies for leveraging it effectively.
Key Takeaways
- The CMC Altcoin Season Index evaluates the performance of top 100 altcoins against Bitcoin over 90 days.
- Altcoin Season is triggered when 75%+ of altcoins outperform Bitcoin; below 25% signals Bitcoin Season.
- Daily updates reflect shifting market momentum, aiding portfolio adjustments and trend identification.
- Traders use the index to avoid late-stage hype cycles and capitalize on emerging opportunities.
👉 Explore crypto trends with confidence
Understanding the CMC Altcoin Season Index
The Altcoin Season Index measures relative strength between Bitcoin and major altcoins. Here’s how it breaks down:
- 0–25: Bitcoin Season (BTC dominance).
- 26–74: Neutral phase (mixed performance).
- 75–100: Altcoin Season (altcoins lead).
Calculation Methodology
- Top 100 altcoins (excluding stablecoins/wrapped tokens) are analyzed.
- Each coin’s 90-day return is compared to Bitcoin’s.
- The percentage of altcoins outperforming BTC determines the index value.
Example: An index value of 23/100 (July 2025) indicates only 23% of altcoins beat Bitcoin—a clear Bitcoin Season.
Why the Index Matters
- Altcoin Season: Often brings rapid gains for smaller-cap projects as capital rotates from BTC.
- Bitcoin Season: Suggests consolidation around BTC, with altcoins stagnating despite positive news.
👉 Stay ahead of market rotations
Practical Applications for Traders
Spotting Momentum Shifts
- Index values above 50 may signal growing altcoin strength.
Portfolio Adjustments
- Increase altcoin exposure during upward index trends.
Risk Management
- High values (90+) can indicate overbought conditions.
Defensive Strategies
- In Bitcoin Season, focus on BTC or large-cap coins.
Historical Trends
- December 2024: Index peaked at 87 (Altcoin Season).
- April 2025: Dropped to 12 (Bitcoin Season).
These swings highlight market volatility and the need for adaptability.
Pro Tips for Using the Index
- Combine Indicators
Pair with volume analysis, dominance charts, and on-chain data. - Avoid Overreliance
Use alongside fundamental research—never as a standalone signal. - Watch for Divergence
If the index rises but major altcoins lag, assess sector-specific trends.
FAQs
What does an index value below 25 signify?
It confirms Bitcoin Season, with most altcoins underperforming BTC.
Is Ethereum included in the index?
Yes. Despite its market size, ETH is classified as an altcoin here.
How frequently is the index updated?
Daily, reflecting the latest 90-day performance data.
Can the index predict altcoin rallies?
No—it tracks past performance but helps identify emerging trends.
Should I base trades solely on this index?
No. Always integrate additional analysis tools for informed decisions.
Final Thoughts
The CMC Altcoin Season Index demystifies market cycles, offering actionable insights for traders and long-term investors alike. While Bitcoin currently leads (as of July 2025), altcoin seasons can emerge swiftly—making this indicator a vital tool for strategic decision-making.