What is the Altcoin Season Index?
The Altcoin Season Index shows how many of the top 100 altcoins have outperformed Bitcoin over the past 90 days. It returns a score from 0 to 100, giving you a quick read on the current market regime: Are we in an Altcoin Season, or a Bitcoin Season?
Thresholds
| Index score | Market phase | What it means |
|---|---|---|
| 0–25 | Bitcoin Season | Bitcoin clearly dominates; most altcoins underperform |
| 26–49 | No Altcoin Season | Transition phase with a bias toward Bitcoin Season |
| 50–74 | No Altcoin Season | Transition phase with a bias toward Altcoin Season |
| 75–100 | Altcoin Season | Broad altcoin outperformance versus Bitcoin |
How does the Altcoin Season Index work?
Methodology
The index is calculated in a few steps:
Universe: Select the top 100 altcoins by market cap (excluding stablecoins, wrapped/pegged tokens, liquid staking derivatives, etc.)
Time window: Calculate performance over the last 90 days
Benchmark: Compare each altcoin’s performance to Bitcoin over the same period
Count: Count how many altcoins beat Bitcoin
Score: Convert the result into a 0–100 index value
Example: If 45 out of 100 altcoins outperform Bitcoin, the Altcoin Season Index is 45.
Which coins are excluded from the index?
The index aims to measure altcoins that can outperform Bitcoin on their own. Some token types don’t have an independent price path, so they’re excluded:
Stablecoins: Pegged to fiat (usually the U.S. dollar) and designed to be price-stable. Examples: Tether (USDT), USDC, DAI
Wrapped and pegged tokens: Tokenized representations of other assets that largely mirror the underlying price. Examples: WBTC (tracks BTC), WETH (tracks ETH)
Liquid staking derivatives (LSDs): Tokens that closely follow the staked base asset (plus staking yield). Examples: stETH, rETH, cbETH
Note: Protocol tokens like LDO (Lido) or RPL (Rocket Pool) are included because they can develop independent value. The liquid staking derivatives issued by these protocols (stETH, rETH), however, are excluded.
Limitations of the Altcoin Season Index
The Altcoin Season Index is a useful tool, but it comes with important limitations:
Lagging indicator: It’s based on the last 90 days of performance. It reflects past behavior, not future outcomes.
No weighting: An altcoin that beats Bitcoin by 10% counts the same as one that beats it by 200%.
Top-100 focus: Only large-cap coins are included. Small caps and very new projects are not reflected.
Fixed window: A 90-day lookback may miss shorter “mini altseasons” that play out over just a few weeks.
That’s why it’s best used alongside other indicators such as Bitcoin dominance, trading volume, and sentiment metrics.
What is Altcoin Season?
Altcoin Season (often called “Altseason”) is a market phase where altcoins broadly outperform Bitcoin. By definition, altcoins are all cryptocurrencies other than Bitcoin. During Altseason, capital tends to flow into higher-risk crypto assets, driving outsized moves across many altcoins.
Altseason often coincides with declining Bitcoin dominance (Bitcoin’s share of total crypto market cap), as investors rotate profits from Bitcoin into riskier opportunities.
When does Altcoin Season usually start?
Altcoin Season typically follows a strong Bitcoin rally and often looks like this:
Bitcoin rallies hard and makes new highs
Market sentiment improves
Bitcoin dominance peaks and starts to fall
Ethereum shows relative strength (ETH/BTC rises)
Capital rotates from Bitcoin into large-cap altcoins, then mid-caps, then small-caps
Bitcoin often acts as the “gateway” asset. Without a prior Bitcoin-led rally, sustained Altcoin Seasons are less common.
How long does Altcoin Season last?
Duration varies widely, but it often ranges from 4 to 12 weeks. The Altseason in early 2021 lasted roughly four months (February to May), while shorter phases may play out over only a few weeks.
Altseasons can also end abruptly. If Bitcoin corrects sharply or macro conditions reduce risk appetite, the rotation can reverse quickly.
What are the signals of an Altcoin Season?
Falling Bitcoin dominance: As Bitcoin’s market share declines, capital typically rotates into altcoins. This signal is more meaningful if the total market is stable or rising.
Altcoins outperform Bitcoin on a relative basis: It’s not enough for altcoins to go up—many need to rise faster than Bitcoin, often visible in BTC pairs like ETH/BTC or SOL/BTC.
Improving market breadth: A “real” Altseason isn’t just 2–3 coins pumping—many projects move higher together.
Rising altcoin volume: More activity outside Bitcoin, such as higher spot volume and increasing open interest in altcoin futures.
Narrative rotation: Attention shifts from “Bitcoin only” to sectors like AI, DeFi, gaming, or memecoins—and narratives rotate quickly.
Why does capital rotate from Bitcoin into altcoins?
The rotation often follows a familiar pattern:
Bitcoin as the entry point: Many new investors start with Bitcoin.
Profit-taking: After a Bitcoin run, investors look for higher upside elsewhere.
Higher risk appetite: Bull markets increase willingness to take risk.
Narratives: Emerging trends (DeFi, NFTs, AI, etc.) attract capital into specific altcoin sectors.
About the author
Hi, I'm Philipp. 👋
Founder coinbird.com
With over 15 years of experience in the IT sector, I love building easy-to-use digital products that actually help people. In 2017, I fell down the Bitcoin rabbit hole and gradually realized that the crypto world lacked simple, user-friendly tools for everyday people. That’s why I created coinbird.com – to make crypto easier to understand, more accessible, and transparent.
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