Altcoin Season Index: Complete explanation and analysis

In crypto, the focus is often on Bitcoin and altcoins, meaning all alternative coins. Bitcoin frequently performs strongly, but at times altcoins gain much more momentum and enter a period in which these cryptocurrencies outperform. This period is called altcoin season or altseason, a phase where alternative cryptocurrencies perform better than Bitcoin.

The Altcoin Season Index helps investors determine where we are in this cycle and can provide insight into market sentiment and opportunities. At Coinmerce, we believe that knowledge is the foundation of successful decision-making. That‘s why, in this guide, we explain what the Altcoin Season Index is, how it works, and how you can use it to strengthen your strategy.

Key takeaways:

The Altcoin Season Index measures when altcoins outperform Bitcoin.

A score above 75 often indicates an altseason.

Factors such as Bitcoin dominance, market sentiment, and profit-taking play a role.

You can use the index to identify market phases and tailor your strategy accordingly.

What is the Altcoin Season Index?

The Altcoin Season Index is a measurement tool that shows whether the market is in a Bitcoin-dominated or altcoin-dominated phase. The index compares the performance of the 50 largest altcoins with that of Bitcoin over a specific period, usually 90 days. When more than 75% of these altcoins outperform Bitcoin, we refer to this as altcoin season, or altseason for short. The index is popular among traders and analysts because it helps identify trend shifts. It combines historical price data, market dominance and momentum to determine where capital is flowing.

What is altcoin season?

An altcoin season is the period in which altcoins — such as Ethereum, Solana, Avalanche and Cardano — show stronger price gains than Bitcoin. These periods are often characterised by rising market sentiment, increasing trading volumes and declining Bitcoin dominance. Altseason is not merely a hype phase; it often reflects a broader shift in market confidence toward innovation and higher-risk assets.

When does altseason start?

Altseason typically begins after a strong Bitcoin rally. Once Bitcoin stabilises and investors start taking profits, capital often flows into altcoins. The exact timing varies by cycle, but indicators such as decreasing Bitcoin dominance and increasing altcoin volume are early signals.

How long does altseason last?

Its duration varies significantly per cycle, ranging from several weeks to several months. The peak phase is often short, followed by sharp corrections. Historically, the altseason of 2021 lasted roughly three months.

How often does altcoin season occur?

Altseasons follow no fixed pattern, but they tend to appear once or twice per Bitcoin cycle on average. Factors such as macro-economic conditions, regulation and technological developments play a role.

What exactly does the index measure?

The index analyses the performance of the top 50 altcoins compared to Bitcoin over 90 days. If 38 of the 50 altcoins (76%) outperform BTC, this is considered an altcoin season.

Which altcoins are included in the index?

The composition varies, but generally includes the largest projects by market capitalisation, such as Ethereum (ETH), BNB, Solana (SOL), XRP, Cardano (ADA), Avalanche (AVAX) and Polkadot (DOT).

How do you recognise an altseason?

You don‘t recognise an altseason by one single signal, but by a combination of factors. It is often the result of a shift in market dynamics where investors become more willing to take risks. This shift is accompanied by increasing trading volume in altcoins, growing interest on social media and a rising number of projects launching new technology or applications. While Bitcoin sets the tone for the market, altcoins showcase how broad and innovative the crypto world truly is. By recognising these patterns early, traders can better anticipate momentum and seize opportunities before the majority does.

Bitcoin dominance

Bitcoin dominance indicates what percentage of the total crypto market value consists of Bitcoin. When this percentage falls, capital often moves towards altcoins — a classic signal of an upcoming altseason.

75% of top altcoins outperform Bitcoin

When most of the top altcoins outperform Bitcoin, this confirms a shift in market dynamics. The Altcoin Season Index uses this percentage as its core indicator.

Sentiment shifts from BTC to altcoins

During an altseason, market sentiment shifts: traders seek higher returns outside of Bitcoin. Social media activity, search volume and increased activity in DeFi (decentralised finance) or NFTs (non-fungible tokens) reinforce this effect.

How do I determine my strategy using the Altcoin Season Index?

The Altcoin Season Index is not a buy or sell signal, but a tool for interpreting market trends. Some strategies include:

Diversification: During an altseason, you might temporarily allocate more to altcoins with strong fundamentals.

Risk management: Altcoins are more volatile. Use the index to plan profit-taking moments.

Cyclical trading: When the index peaks, it may be wise to move (part of) your profits back into Bitcoin or stablecoins.

How do you use the index to predict altseason?

Although the index provides historical insight, it can also support forecasts. An upward trend in the Altcoin Season Index may indicate growing confidence in altcoins. Combine the index with on-chain data such as exchange inflows, social media sentiment analysis, and technical indicators like RSI or market dominance.

Will there be an altseason in 2026?

It‘s difficult to say with certainty. Historically, altseasons often follow Bitcoin halvings, when the supply of new Bitcoins decreases and the market becomes cyclically more active. The next halving is planned for 2028, making 2026 an interesting mid-cycle year in which capital may temporarily move towards altcoins. However, the market remains dependent on factors such as regulation, economic conditions and blockchain adoption.

Frequently asked questions

Below you‘ll find the most frequently asked questions about altcoins and altseason.

Which altcoins have a future?

Altcoins with strong use cases, active development teams and a growing user base often have the highest chance of long-term relevance. Examples include Ethereum, Solana, Chainlink and Arbitrum.

What are the top 10 altcoins?

The top 10 changes constantly, but typically includes projects such as Ethereum (ETH), BNB, Solana (SOL), XRP, Cardano (ADA), Toncoin (TON), Dogecoin (DOGE), Avalanche (AVAX), Chainlink (LINK) and Polygon (MATIC).

Will there be an altseason in 2026?

An altseason in 2026 is possible, especially if the market enters a recovery phase and investors regain risk appetite. Keep an eye on the Altcoin Season Index to identify trends early.

When will the next altseason occur?

There is no fixed timing, but altseasons often follow several months after strong Bitcoin rallies. Falling Bitcoin dominance and rising altcoin volumes are important signals.

Want to learn more about altcoins?

Want to dive deeper into altcoins? Discover more about altcoins such as Ethereum, Solana and Polkadot. At Coinmerce, you can easily buy, store and trade these and other altcoins — all within one secure, Dutch platform.