Altcoin Season Indicator CMC: How to Read and Understand It?

Timing the crypto market can feel like trying to catch lightning in a bottle. One day Bitcoin is soaring, the next day altcoins are stealing the spotlight. To help investors track when altcoins are outperforming, CoinMarketCap developed the Altcoin Season Index—a clear, data-driven indicator that reveals whether we’re in Bitcoin Season or Altcoin Season.

If you’re wondering how this index works, what the numbers mean, and how to use it to sharpen your strategy, this guide breaks everything down step by step.

Read Also: Altcoin ETF Summer May Begin in July with SEC Approvals

Key Takeaways

• The CMC Altcoin Season Index measures how the top 100 altcoins perform relative to Bitcoin over 90 days.
• If 75% of these altcoins outperform BTC, it’s officially Altcoin Season.
• The index updates daily, showing whether market momentum favors altcoins or Bitcoin dominance.
• Traders use it to adjust portfolios, spot trends, and avoid chasing hype too late.

Register now on Bitrue — a trusted crypto exchange used by millions worldwide. Bitrue gives you access to hundreds of tokens, low-fee trading pairs, and high-yield staking opportunities. Whether you're buying Bitcoin, trading altcoins, or exploring new DeFi projects, Bitrue makes it easy to get started. Sign up today and start your crypto journey in minutes.

What Is the CMC Altcoin Season Index?

The Altcoin Season Index is a metric that shows whether the majority of top altcoins are outperforming Bitcoin. Developed by CoinMarketCap, it compares the 90-day performance of the top 100 altcoins (excluding stablecoins and asset-backed tokens) against Bitcoin’s price returns over the same period.

If less than 25% of altcoins outperform BTC, it’s considered Bitcoin Season. If more than 75% outperform BTC, it’s Altcoin Season. Anything in between is a transitional phase.

This simple threshold approach gives a clear picture of which part of the market has momentum and helps investors decide where to focus.

How to Read the Altcoin Season Indicator

Reading the index is straightforward. The number ranges from 0 to 100:

• 0–25: Bitcoin Season. Most altcoins are lagging behind BTC.
• 26–74: Neutral Zone. No clear dominance by Bitcoin or altcoins.
• 75–100: Altcoin Season. Altcoins are outperforming Bitcoin decisively.

For example, as of July 2025, the index shows 23/100, signaling that we are still in Bitcoin Season. Over the past 90 days, only 23% of the top 100 altcoins have outperformed BTC.

Why Does This Matter?

Altcoin Season can bring explosive gains across smaller coins as traders rotate profits out of Bitcoin. Conversely, in Bitcoin Season, liquidity and attention often consolidate around BTC, causing altcoins to stagnate or even decline despite positive headlines.

By watching the index, investors avoid jumping into altcoins just as momentum fades. Instead, they can position early when the indicator starts trending toward Altcoin Season.

Read Also: Altcoin Season Index: A Guide to Understanding Altseason Index

What Coins Are Included?

The index uses the top 100 coins by market cap except for:

• Stablecoins like USDT and DAI.
• Wrapped or asset-backed tokens like WBTC, stETH, and cLINK.

Ethereum is included in the index and technically considered an altcoin for this purpose, even though it’s the largest one.

How Is the Index Calculated?

Here’s a simple version of the calculation:

1. Take the top 100 eligible altcoins.
2. Compare each coin’s performance to Bitcoin over the last 90 days.
3. Count how many coins performed better.
4. Divide by 100 to get the percentage.

For example, if 80 out of 100 coins outperformed Bitcoin, the index would show 80/100, signaling Altcoin Season.

How Can Traders Use the Index?

The Altcoin Season Index is not a perfect predictor, but it’s a valuable sentiment gauge. Here are some ways traders use it:

• Spot Market Rotations: When the index climbs above 50, it often signals growing altcoin momentum.
• Adjust Exposure: Investors may increase altcoin allocations if the trend is toward Altcoin Season.
• Take Profits: A high index near 90+ can be a warning that the altcoin rally is overheated.
• Stay Defensive: In Bitcoin Season, focusing on BTC or large-cap coins can reduce risk.

Historical Context and Yearly Highs

Over the past year, the index has swung between extremes:

• Yearly High: 87 (Altcoin Season in December 2024)
• Yearly Low: 12 (Bitcoin Season in April 2025)

These swings show how quickly market sentiment can shift, reminding traders to stay flexible.

Tips for Using the Altcoin Season Indicator

If you’re using this index in your strategy, here are a few practical tips:

• Always combine it with other indicators like volume, dominance charts, and on-chain activity.
• Don’t rely solely on it for buy or sell decisions.
• Watch for divergence between the index and major altcoins. If the index rises but Ethereum lags, it could signal selective rotation.

Final Thoughts

The CMC Altcoin Season Index is a simple but powerful tool to understand market dynamics between Bitcoin and altcoins. Whether you’re a trader or a long-term investor, watching this index can help you time rotations, manage risk, and avoid being caught on the wrong side of momentum.

As of now, Bitcoin still holds the spotlight, but history shows that when altcoin season comes, it can arrive fast and shake up portfolios. Keep an eye on this indicator—it could be the edge you need to navigate the cycles ahead.

Read Also: Top Altcoin July 2025: Whales Watch This Project

FAQs

What does it mean when the Altcoin Season Index is below 25?

It means we are in Bitcoin Season. Most altcoins are underperforming Bitcoin over the last 90 days.

Is Ethereum considered an altcoin in this index?

Yes. Despite its size, Ethereum is included as an altcoin for this calculation.

How often does the index update?

The index updates daily to reflect fresh 90-day performance data.

Can the index predict altcoin rallies?

It doesn’t predict future rallies but shows whether altcoins have been outperforming, which can help spot trends.

Should I use this indicator alone to make trading decisions?

No. It’s best used with other tools like technical analysis, sentiment metrics, and fundamental research.