What Is Altcoin Season? A Practical Guide

Altcoin season is a period when most of the leading altcoins outperform Bitcoin at the same time. It is not a day when a few small coins jump, and it is not the same as a crypto bull market. It is a broad, sustained shift in relative strength away from Bitcoin.

A definition you can measure

“Altcoin season” started as trader slang, so it gets used loosely. This site uses a definition that can be checked with data: altcoin season is when at least 75% of the 50 largest eligible altcoins have beaten Bitcoin’s return over the past 90 days. When 25% or fewer are beating it, the market is in Bitcoin season. Anything in between is a mixed or transitional market.

The 90-day window is long enough to filter out a single week of hype, and the top-50 universe is broad enough that one or two tokens cannot swing the result. Stablecoins, wrapped tokens and other assets designed to track something else are left out, because they would distort a comparison between risk assets. The full rules are in the methodology.

One day at 75 is a threshold reading, not yet a season. This site calls an altcoin season confirmed only when the index is 75 or more and Bitcoin dominance is 42% or less on the same day.

A worked example

Say Bitcoin rose 12% over the last 90 days. Of the 50 eligible altcoins, 39 rose by more than 12% over the same window, and 11 either rose less or fell. The index is 39 ÷ 50 × 100 = 78, which is above 75, so it counts as altcoin season.

Now say Bitcoin fell 20% and 30 altcoins fell by less than that. The index is 60, even though almost everything lost money in dollar terms. That is the key point: the index measures performance against Bitcoin, not against the dollar. A falling market can still favor altcoins, and a rising market can still favor Bitcoin.

You can check the current reading, and how it compares with the 30-day and 7-day windows, on the live Altcoin Season Index.

Altcoin season is not the same as a bull market

Many altcoins can rise strongly in dollars while still losing ground to Bitcoin. That happened for long stretches of 2023 and 2024: prices across the market recovered, but Bitcoin recovered faster, helped by the launch of US spot Bitcoin ETFs, and its dominance climbed above 50% and then 60%. Holders of most altcoins made money in dollars but would have done better holding Bitcoin. That is a bull market without an altcoin season.

The reverse also matters. Towards the end of a cycle, altcoins can outperform on the way up and then fall much further than Bitcoin on the way down. Relative strength tells you where the market’s risk appetite is, not whether prices are about to rise.

How an altcoin season usually develops

No two cycles are identical, but past rotations have tended to follow a similar order, as money moves from the safest part of the crypto market towards the most speculative:

1. Bitcoin leads. New money and confidence arrive in Bitcoin first. Bitcoin dominance rises and the index sits low.
2. Ethereum catches up. Once Bitcoin’s move slows, Ethereum often starts to outperform. The ETH/BTC ratio is one of the earliest signs of rotation.
3. Large caps follow. Strength spreads to other top-20 assets. The index climbs through the 50s and 60s as more of the top 50 beat Bitcoin.
4. Breadth reaches smaller coins and narratives. Mid- and small-cap tokens and hot sectors (in past cycles: ICOs, DeFi, NFTs, memecoins, AI) run hardest. This is usually when the index crosses 75.
5. Euphoria and exhaustion. Trading volume, leverage and retail attention peak. Moves become extreme and short-lived, and the rotation often reverses sharply.

Not every cycle completes every stage. Rotations can stall at stage two or three and fall back to Bitcoin leadership without ever reaching a full altcoin season.

Past altcoin seasons

Late 2017 to early 2018

The classic example. Bitcoin’s share of total crypto market capitalization fell from roughly 85% in early 2017 to around a third by January 2018, as money poured into Ethereum, XRP and hundreds of new tokens launched through initial coin offerings. Most of those gains were given back during 2018, when altcoins as a group fell much further than Bitcoin.

Early to mid 2021

After Bitcoin’s rally in late 2020, Bitcoin dominance fell from about 70% at the start of 2021 to around 40% by May. Ethereum, DeFi tokens, large-cap platforms and memecoins all outperformed. The May 2021 crash ended the broadest phase, though individual sectors such as NFTs and gaming tokens stayed strong into the autumn.

2022 to 2024: a long Bitcoin season

The 2022 bear market, the collapse of several large crypto lenders and exchanges, and then the arrival of spot Bitcoin ETFs kept Bitcoin in the lead for most of this period. Short altcoin rallies happened, but breadth rarely held long enough to count as a season on a 90-day view.

You can see how the index has behaved over the history this site has recorded on the index history page.

Signals worth combining

No single number confirms altcoin season. The more of these point the same way, the stronger the case:

• Rising breadth. A growing share of altcoins beating Bitcoin on the 90-day index, with the 30-day and 7-day readings above it, which shows the move is accelerating rather than fading.
• Falling Bitcoin dominance. Bitcoin’s share of the market shrinking, ideally below levels it has respected in the past. The Bitcoin dominance chart tracks this and marks the rotation threshold.
• Ethereum strength. ETH outperforming BTC is often the first link in the chain.
• Participation across sectors. Several unrelated sectors outperforming at once, rather than a single narrative. Compare them on trending narratives.
• Rising altcoin volume. Price moves backed by more trading, not just thin order books.
• Sentiment that is improving but not extreme. Extreme greed and very high leverage tend to show up near the end of a rotation, not the start. See market sentiment.

False signals to watch out for

• One big mover. A single large-cap breakout or a memecoin mania can make headlines without most altcoins participating. Breadth is the whole point.
• Dominance falling for the wrong reason. Bitcoin dominance can drop because stablecoin supply grows, not because altcoins are rising. Check whether altcoins are actually beating Bitcoin before reading anything into it.
• A short window. A 7-day index reading of 80 after one strong week says little about the cycle. Look for the 90-day reading to confirm.
• A market-wide crash. When everything falls, altcoins with less liquidity sometimes fall less for a few days. That is noise, not a rotation.

The risks during an altcoin season

Altcoin seasons are when the biggest gains and the biggest losses in crypto tend to happen. Smaller tokens have thinner liquidity, so they move further in both directions. Late in a rotation, leverage builds up and corrections of 50% or more in a matter of weeks are common. Many tokens that lead one altcoin season never recover their highs. Knowing the market is in altcoin season does not tell you which assets will keep going, or when the phase will end.

How to use the index

• Use the 90-day reading as the main view of where the cycle stands.
• Use the 30-day and 7-day readings to see whether breadth is building or fading.
• Read it together with Bitcoin dominance and which altcoins are outperforming, so you know what is driving the number.
• Set a market alert if you want to know when the index crosses a level, rather than checking every day.

Treat the index as context, not as a buy or sell signal. It describes what has already happened across a broad group of assets. It does not predict what any single coin will do next.

Common questions

How long does altcoin season last?

The broad phases of past cycles lasted from several weeks to a few months. Sector rotations inside them can be much shorter. There is no fixed schedule, and some cycles never produce a full altcoin season.

Does Ethereum count as an altcoin?

On this site, yes. Some methodologies treat Ethereum separately, but it is included here because it is one of the clearest early indicators of rotation away from Bitcoin.

Is altcoin season predictable?

Not reliably. The signals above show when conditions are improving, but rotations can stall or reverse without warning. That is why the index describes the market rather than forecasting it.

For the opposite regime, read altcoin season vs Bitcoin season. For the wider cycle, see crypto market cycle phases.