The altcoin season index sits at 45 as of late February 2026, and if you've been watching your altcoin portfolio bleed while Bitcoin holds relatively steady at $67,586, you probably already feel what that number is telling you. It's not altcoin season. Not even close.
But that reading alone doesn't mean much unless you understand what the index actually measures, what drives it to shift, and how experienced traders use it to time their moves between Bitcoin and everything else. This guide breaks down how the altcoin season index works, what the current reading means for your portfolio, and the signals worth watching as we head into spring 2026.
What the altcoin season index actually measures
The altcoin season index tracks whether altcoins as a group are outperforming Bitcoin over a rolling 90-day window. The most widely referenced version, maintained by Blockchaincenter.net, looks at the top 50 cryptocurrencies by market cap (excluding stablecoins and wrapped tokens) and compares their price performance against BTC over the previous 90 days.
The scoring works like this:
- If 75% or more of those top 50 coins beat Bitcoin's 90-day return, the index declares "Altcoin Season"
- If 25% or fewer outperform Bitcoin, it's "Bitcoin Season"
- Anything between 25% and 75% falls into a neutral zone
CoinMarketCap runs a similar version using the top 100 coins. Their reading currently sits around 31 - firmly in Bitcoin territory. The slight difference between platforms comes down to methodology: CMC uses a larger sample and may weight things differently, but the conclusion is the same right now.
What catches people off guard is the 90-day lookback. The index isn't reacting to what happened yesterday. It's averaging three months of relative performance. That means it lags. By the time the index officially flips to "altcoin season," the early movers have already been rotating into alts for weeks.
Why we're stuck in Bitcoin season right now
With Bitcoin dominance hovering around 59-60% and the Fear and Greed Index at an extreme low of 9, the market is doing exactly what it tends to do during periods of high uncertainty: consolidating into the largest, most liquid asset.
This pattern has played out in every major correction since 2018. When macro conditions tighten or sentiment collapses, capital doesn't leave crypto entirely - a lot of it flows from smaller altcoins into Bitcoin. BTC acts as a relative safe haven within the crypto ecosystem. Traders and funds that want exposure but lower volatility park in Bitcoin, which pushes dominance higher and the altcoin season index lower.
Right now, several forces are keeping dominance high:
- Extreme fear sentiment - The Fear and Greed Index at 9 means almost nobody is willing to take risk on smaller assets. ETH is down at $1,948, and most mid-cap alts have fared worse.
- Ongoing ETF dynamics - Bitcoin ETF outflows have persisted for five consecutive weeks, but the ETF infrastructure still channels institutional attention toward BTC rather than alts.
- Liquidation cascades - Altcoin positions using borrowed capital get wiped out faster in drawdowns, which accelerates the rotation into Bitcoin. Anyone who's watched a liquidation cascade knows how quickly this can drain altcoin market caps.
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How to read the altcoin season index like a trader
Most people treat the index as a binary signal - "it's altcoin season" or "it's not." That's the least useful way to use it.
The real value is in tracking the direction and rate of change. Here's what experienced traders actually watch for:
The climb from 25 to 50: This transition zone is where early positioning happens. When the index starts ticking up from deep Bitcoin-season territory, it usually means a few large-cap alts (often ETH first) are beginning to outperform BTC. Traders who wait for the index to hit 75 before buying alts are consistently late.
Bitcoin dominance divergence: The strongest altcoin season signals come when the altcoin season index is rising while Bitcoin dominance is simultaneously declining. If the index climbs but dominance stays flat, it can be a head fake driven by a small number of outlier altcoins rather than broad-based rotation.
The 90-day lookback trap: Because the index uses a 90-day window, a single month of strong altcoin performance won't move it much. This means the index is always somewhat backward-looking. Pairing it with a 30-day or weekly comparison of altcoin vs. BTC performance gives you faster signals.
Volume confirmation: Rising index values backed by increasing altcoin trading volume carry more weight than index moves on thin volume. Thin-volume rallies in altcoins tend to reverse quickly.
What signals could trigger the next altcoin season
Altcoin seasons don't appear randomly. Looking at historical market cycles, they tend to follow a specific sequence:
- Bitcoin rallies first and establishes a new range
- BTC consolidates sideways for weeks, dominance plateaus
- Capital rotates into large-cap alts (ETH, SOL, etc.)
- As large-caps run, profits flow down to mid-caps and eventually small-caps
- The altcoin season index crosses 75, media attention peaks, and the rotation often reverses shortly after
For the current cycle, the triggers worth monitoring include:
- Bitcoin stabilization above key support - BTC needs to stop making lower lows. A sustained hold above $65,000-$70,000 for several weeks would be the foundation for any altcoin rotation.
- Fear and Greed recovery - The index needs to climb back above 25-30 before risk appetite returns broadly. At 9, we're in capitulation territory where survival matters more than speculation.
- ETH/BTC ratio reversal - The ETH/BTC pair has been one of the most reliable leading indicators for altcoin season. When Ethereum starts consistently gaining against Bitcoin, it usually signals broader altcoin strength ahead.
- Macro relief - Rate cut expectations, trade policy clarity, or any reduction in geopolitical tension tends to bring risk appetite back to crypto's long tail.
Common mistakes traders make with the altcoin season index
I see the same errors repeated every cycle.
Buying alts because the index is low. A low index reading tells you alts are underperforming, but it doesn't tell you they're about to stop underperforming. "Cheap" can get cheaper. The index can stay below 25 for months - the current Bitcoin season streak has lasted 149 days according to Blockchaincenter data.
Treating all altcoins as one trade. Even during confirmed altcoin seasons, the performance spread between the best and worst alts is enormous. Some coins 10x while others barely move. The index tells you about the group, not which specific coins will lead.
Ignoring Bitcoin's trend. If Bitcoin is actively crashing, a rising altcoin season index might just mean alts are falling less slowly than BTC. That's technically outperformance, but it's not the kind you want to be buying into.
Chasing the index at 75+. By the time the index officially confirms "altcoin season," you're often buying the top of the rotation. The average altcoin season on Blockchaincenter's data lasts only about 17 days. If you enter late, you're likely catching the tail end.
Building a strategy around the altcoin season index
Rather than using the index as a buy/sell signal, think of it as one input in a broader framework. Here's an approach that accounts for its limitations:
Below 25 (deep Bitcoin season): Focus on accumulating Bitcoin or stablecoins. Research which altcoins you'd want to own when conditions shift. This is preparation time, not deployment time. Consider using dollar-cost averaging into your top conviction picks if you have a multi-month horizon.
25-50 (transitioning): Start small positions in large-cap alts, particularly ETH. Watch the ETH/BTC ratio closely. If dominance starts declining alongside a rising index, begin scaling in more aggressively.
50-75 (heating up): Rotate more actively into mid-cap altcoins with strong fundamentals. This is where the best risk-reward window typically sits.
Above 75 (confirmed altcoin season): Be cautious about adding new positions. Start planning your exit strategy and rotating profits back into BTC or stablecoins. Remember - 17 days is the average duration. The crowd just arrived, which historically means the smart money is already leaving.
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The bottom line
The altcoin season index is a useful compass, not a GPS. It tells you the general direction of capital rotation in crypto, but it won't tell you exactly when to buy or which coins will outperform. At 45 with Bitcoin dominance near 60% and fear at record lows, the market is clearly in wait-and-see mode.
The traders who do well through these transitions are the ones preparing now - building watchlists, accumulating stablecoins, studying which sectors (AI tokens, DeFi, Layer 2s) are likely to lead the next rotation. When the index starts climbing and dominance starts falling, the window opens fast and closes faster.
If you're holding altcoins through this period, managing your risk with proper position sizing and risk controls matters more than trying to time the exact bottom.