How to Tell if It Is Altcoin Season

Learn the published rule for altcoin season, how the 90-day index is calculated, what it excludes, and how to read the three indicator bands.

Updated October 2026 · Reviewed by the PipeFlare team

It is officially Altcoin Season under the widely cited Blockchain Center rule when at least 75% of the top 50 coins outperform Bitcoin over the last 90 days.

The index provides an objective 90-day mathematical metric so you do not have to guess market conditions from the news.

About alt season

You can tell if it is alt season by checking a published mathematical rule rather than guessing from the news. Under the widely cited standard published on Blockchain Center, the rule states: "If 75% of the Top 50 coins performed better than Bitcoin over the last season (90 days) it is Altcoin Season." This calculation converts market performance across the leading digital assets into a single number between 0 and 100. By measuring price performance relative to Bitcoin over a rolling three-month window, the benchmark provides an objective reference point for observers tracking market behavior. Blockchain Center updates this index daily, giving market watchers a consistent way to track rolling performance trends. The benchmark defines three distinct performance bands across its 0 to 100 scale. Bitcoin Season is registered when the index reading sits at 25 or lower, signaling that the majority of top assets are trailing Bitcoin. A neutral market environment occupies the middle zone between 26 and 74. Altcoin Season is reached only when the gauge hits 75 or higher, demonstrating that three-quarters of qualifying large-cap tokens have outperformed Bitcoin over the preceding 90 days. Alongside the standard 90-day season calculation, the site also displays Month and Year metrics to show shorter and longer comparative periods. This index serves strictly as a backward-looking label of what already happened over the prior 90 days rather than a forecast of future prices. An index reading above 75 means altcoins have already beaten Bitcoin across the past quarter; it does not indicate that this trend will continue tomorrow or next week. For broader context on the foundational digital currency used as the baseline for this comparison, review the explainer on what is Bitcoin. Because live market conditions change continuously, this page does not print a static reading that could become obsolete tomorrow. Observers can look up the current figure directly on Blockchain Center whenever they need an up-to-date reading. Readers should also note that Blockchain Center's formula represents one published methodology, while other market tracking services may employ different parameters or calculation rules.

How it actually works

The Altcoin Season Index measures the percentage of qualifying large-cap cryptocurrencies that outperform Bitcoin across a rolling 90-day window. To generate this figure, the calculation reviews the top 50 coins and tracks their individual percentage returns against Bitcoin over that three-month timeframe. When 75% or more of those 50 assets record a higher percentage gain than Bitcoin over the period, the index registers an Altcoin Season. The calculation updates on a daily schedule to reflect shifting 90-day returns.

Certain categories of digital tokens are deliberately removed from the top 50 list before the calculation occurs. The index excludes stablecoins such as Tether and DAI from the top 50 list. The formula also excludes asset-backed tokens, including WBTC, stETH, and cLINK.

While the 90-day Season figure serves as the primary gauge, the index page provides complementary timeframes to broaden analysis. Readers can view separate Month and Year indicators alongside the main 90-day figure to compare short-term shifts against annual performance. The site also publishes historical statistics for each distinct season classification, including the days elapsed since the last season, the average days between seasons, the longest streak, and the average length of a season. Because these historical values update over time, visitors should consult Blockchain Center directly to examine the current figures.

The index is a different metric from Bitcoin dominance, even though traders frequently link the two concepts. As detailed in the site's guide on Bitcoin dominance, dominance measures Bitcoin's percentage share of the entire cryptocurrency market capitalization. When dominance falls, market participants often describe the environment as an alt season. However, the two can disagree because dominance counts market-cap share while the index counts how many of 50 coins beat Bitcoin over 90 days. Global market-cap charts and dominance statistics can be verified through CoinGecko.

A primary operational limitation of the index is the mathematical lag inherent in a 90-day lookback window. This lagging nature reinforces why the indicator functions as a historical classification system rather than an early warning tool.

Start here

1Navigate to the official [Blockchain Center](https://www.blockchaincenter.net/en/altcoin-season-index/) website to view the current Altcoin Season Index dashboard.
2Observe the primary 90-day indicator to identify whether the current reading sits in the Bitcoin Season zone (0 to 25), Neutral territory (26 to 74), or Altcoin Season (75 to 100).
3Examine the complementary Month and Year index readings displayed on the page to understand how shorter and longer timeframes compare to the 90-day season metric.
4Cross-reference the index reading against overall Bitcoin dominance metrics on [CoinGecko](https://www.coingecko.com/en/global_charts) to compare coin performance against aggregate market capitalization share.
5Confirm that your understanding of the current top-50 asset pool accounts for the exclusion of stablecoins like Tether and DAI as well as wrapped tokens like WBTC and stETH.
6Review the published historical statistics on the page, including the duration of past seasons and streaks, while remembering that past 90-day performance describes history rather than predicting future market movements.
7Refrain from sizing trades or reallocating portfolios based purely on a single retrospective index number.

Strengths

Provides a clear, objective mathematical threshold based on whether 75% of top qualifying coins outperformed Bitcoin over 90 days, eliminating emotional guesswork.
Removes stablecoins and asset-backed tokens from the top 50 sample.
Updates daily, so anyone can check the current classification without doing the math themselves.
Includes Month and Year comparative views alongside detailed historical records such as average season duration and days between cycles.

Common misunderstandings

Operates as a strictly backward-looking indicator that records what took place over the past 90 days rather than predicting future price action.
Depends on which 50 coins and which source are used for the calculation.
Represents only one specific published definition from Blockchain Center, meaning other analytical platforms may use conflicting criteria.
Can diverge from Bitcoin dominance trends because dominance counts market-cap share while the index counts how many of 50 coins beat Bitcoin over 90 days.

Common questions

How do I tell if it is alt season?

You can tell by checking the published Altcoin Season Index on Blockchain Center. If the gauge reads 75 or higher, indicating that at least 75% of the top 50 qualifying coins outperformed Bitcoin over the preceding 90 days, it is officially classified as Altcoin Season under that standard.

What is the Altcoin Season Index?

The Altcoin Season Index is a mathematical market indicator published by Blockchain Center that measures the relative performance of leading cryptocurrencies against Bitcoin. It calculates the percentage of the top 50 coins that generated higher returns than Bitcoin over a rolling 90-day period on a scale from 0 to 100.

What number means alt season?

An index reading of 75 or higher denotes Altcoin Season. Readings of 25 or lower represent Bitcoin Season, while any reading between 26 and 74 is classified as Neutral territory.

Is alt season the same as Bitcoin dominance falling?

No, they are distinct metrics. Bitcoin dominance measures Bitcoin's share of total crypto market capitalization, as detailed in our guide on Bitcoin dominance, whereas the index tracks the number of individual large-cap coins outperforming Bitcoin. The two can disagree because dominance counts market-cap share while the index counts how many of 50 coins beat Bitcoin over 90 days.

Does the index predict what happens next?

No, the index provides no price predictions or forecasts. It functions entirely as a backward-looking measurement that summarizes price performance over the prior 90 days.

Why are stablecoins excluded?

The calculation excludes stablecoins such as Tether and DAI from the top 50 coins. The index also excludes asset-backed tokens such as WBTC, stETH, and cLINK.

Sources

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