What is Altcoin Season? A Guide to Using the Altcoin Season Index for Crypto Investments in 2026

Financial markets are full of labels used to describe different market conditions. Those labels, however, are only useful when investors share a common understanding of when they apply. Otherwise, the same market may be interpreted differently depending on who is making the assessment.

Similarly, anyone asking what is altcoin season will quickly discover that the answer is not always consistent across the crypto industry. From this issue came its solution - the Altcoin Season Index - one of the most widely used points of reference when evaluating altcoin seasons.

1What Is Altcoin Season?

Altcoin season refers to a period when most major altcoins generate stronger returns than Bitcoin over an extended timeframe. A key requirement is that this outperformance must be broad-based.

Altcoin season is a sustained, broad-based market phase where major altcoins outperform Bitcoin.

This trait is worth keeping in mind, as crypto markets often experience strong altcoin rallies that are confined to a single narrative, such as AI, memecoins, or one Layer 1 ecosystem. While the outperformance may be dramatic, they do not necessarily indicate that the broader altcoin market has taken leadership from Bitcoin.

2Altcoin Season Index: How This Tool Works

What we discussed above likely makes investors wonder how broad, then, is broad enough for altcoin outperformance to qualify as an altcoin season? The key to that question lies in the Altcoin Season Index.

The Index itself is easy to read (which, yes, we will guide you through this process in a later section), but understanding what the index actually represents requires understanding how it is calculated. 

4 steps to use the Altcoin Season Index.

Step 1: Select the Asset Basket

When picking which cryptocurrencies will be included in the Index, providers typically select the largest assets by market capitalization. 

This is because these assets tend to be more liquid and actively traded, making them better representatives of broader market conditions compared to their smaller and thinly traded counterparts. 

Step 2: Exclude Assets Unsuitable for Comparison

The goal of the Altcoin Season Index, again, is to compare how altcoins perform relative to Bitcoin. For that comparison to be meaningful, every asset in the Index must have a price that reflects its own market performance rather than another asset's.

Stablecoins, for instance, are designed to remain close to a fiat currency, while wrapped tokens simply mirror another cryptocurrency. Since neither generates independent price performance, they are almost always excluded from the calculation.

Step 3: Compare Each Altcoin's Performance with Bitcoin

Each altcoin's performance is then compared with Bitcoin over a rolling 90-day period. An altcoin is counted as having outperformed whenever its return exceeds Bitcoin's over the same timeframe. This counts even if both assets generated negative returns.

Step 4: Convert the Results into an Index Score

After every altcoin has been classified as either outperforming Bitcoin or not, the result is converted into a single score:

Altcoin Season Index = (Number of altcoins that outperformed Bitcoin ÷ Total eligible altcoins) × 100

For example, if an Index tracks 100 eligible altcoins and 72 outperform Bitcoin over the previous 90 days, the Index score is 72. This reads as 72% of the tracked altcoins outperformed Bitcoin during the measurement period. 

Then, what does this score tell us about altcoin season?

3How to Interpret the Altcoin Season Index

What the Score Says About Market Conditions

To answer that question, most providers divide the Index into three broad market regimes:

Understand the three broad market regimes in the Altcoin Season Index.

To understand how market leadership is evolving, it is useful to go beyond interpreting the Index one time and instead follow its changes over time.

Look Beyond a Single Score 

The same score can reflect very different market dynamics depending on how it was reached. 

For example, the Altcoin Season Index climbing from 40 to 70 over several weeks would suggest that altcoin participation is broadening. By contrast, a falling score from 90 to 70 points at market leadership concentrating in Bitcoin again.

The duration of the trend is just as important. During the 2021 market cycle, for instance, CryptoRank's Index stayed above 75 for an extended period. The strength of this wave also spread from Ethereum to DeFi protocols and competing Layer 1 networks. 

One final point is that short-term fluctuations are not always meaningful. Because the Index is recalculated every day using a rolling 90-day window, the score can rise or fall as older data drops out of the calculation and newer data is added. This also explains why the Altcoin Season Index can change (dramatically at times) even when there has been little recent price movement. 

Why You Shouldn't Compare Scores Across Providers

If you compare the Altcoin Season Index across different websites, you may notice that they do not always report the same score on the same day. This is because while they all measure the same concept, each implements the methodology slightly differently.

Altcoin Season Index scores can differ across providers depending on each methodology.

Asset basket

Differences in the asset basket can arise in two ways: its size and its composition. 

The basket size varies by provider. For example, BlockchainCenter builds its Index from the top 50 cryptocurrencies, whereas CoinMarketCap and CryptoRank use the top 100.

Even providers that track the same number of cryptocurrencies may not include exactly the same assets, since they update their baskets on different schedules.

Eligibility rules

Although we know that in general, stablecoins and wrapped tokens never make the list, the complete eligibility criteria are not always publicly disclosed. Consequently, providers may have different ideas of what qualifies and whatnot. As the Index is calculated from the eligible asset basket, differences in eligibility can naturally lead to different Index scores.

Price snapshots

Providers may also record market prices at different times of the day. Because the Index is based on 90-day returns, even small differences in the price observation time can lead to slightly different performance calculations and, consequently, different Index scores.

This is why consistently following a single website would provide you a much clearer picture of how market breadth is evolving than constantly switching between providers.

4What the Altcoin Season Index Cannot Tell You

Altcoin Season Index sure is a useful tool for understanding market conditions, but many other questions that matter to investors fall outside its scope.

There are things beyond the Altcoin Season Index.

It Describes the Past, Not the Future

Because every score is calculated from a rolling 90-day window, an Index above 75 simply confirms that widespread altcoin outperformance occurred during that measurement period. It does not indicate whether that trend will continue, weaken, or reverse, and hence, should not be used as a prediction tool.

It Does Not Measure the Whole Market Picture

First, the Index measures how many altcoins outperformed Bitcoin, not by how much. 

As a result, the size of each altcoin's outperformance has no effect on the final score. A market where 80% of tracked altcoins beat Bitcoin by just 1%, therefore, would receive a higher Index reading than one where only 60% outperform Bitcoin by 100%. 

Second, the Index tells you what happened, but not why it happened. To understand the underlying drivers, investors often look at indicators such as Bitcoin Dominance (BTC.D), the ETH/BTC ratio, liquidity, and market sentiment.

Third, the Index is calculated from a predefined basket of large-cap assets. This means thousands of smaller altcoins, even if they have strong performances, likely have no influence on the final score at all.

It Cannot Tell You Which Altcoins Are Worth Buying

The Altcoin Season Index evaluates the market as a whole rather than individual cryptocurrencies.

As a result, it cannot assess project-specific factors such as tokenomics, adoption, liquidity, competitive positioning, governance, or upcoming token unlocks. These factors vary from one cryptocurrency to another and require separate fundamental analysis.

5A Final Word on What is Altcoin Season & Altcoin Season Index

Ultimately, understanding what is altcoin season is not about finding the perfect buy signal, but more so about interpreting the broader market with greater objectivity. The Altcoin Season Index (along with other metrics) is a useful (and commonly used) tool to support that greater goal.

If you're looking for more crypto explainers, market insights, and project breakdowns written with this same approach, Coinminutes has just what you're looking for. Visit https://coinminutes.com/ to stay up to date with our latest research.