Altcoin Season Index: how to read it and what it misses

The Altcoin Season Index is a score between 0 and 100 that tells you which side of the crypto market has had the upper hand: Bitcoin or the altcoins. A high score means altcoins have been doing better than Bitcoin. A low score means Bitcoin has been doing better. An altcoin is any crypto coin other than Bitcoin.

The index itself is published by CoinGlass, a crypto data provider. We do not calculate it. Our page takes the daily CoinGlass series and turns it into a chart, a current reading, a 7-day and 30-day change, and a table of past stretches. We then add two readings of our own that look at the same question from a different side.

The page is public. You do not need an account to see it. In plain terms it answers one question: is the market currently behaving like an altcoin season, yes or no? The glossary has a short definition of altcoin season if the term is new to you.

The page uses two thresholds. A value of 75 or higher counts as Altcoin Season. A value of 25 or lower counts as Bitcoin Season. Anything in between is the middle zone, where neither side is clearly ahead. These are the same cut-offs the page uses everywhere, including in the chart and the streak counter.

Next to the big number you see two change chips, one against 7 days ago and one against 30 days ago. A small marker on the Bitcoin-to-Altcoin bar also shows where the index stood a week ago, so you can see which way it has been drifting. A short sentence below the number tells you how many days in a row the index has been in its current zone, and whether that is the longest such stretch on record.

The index series comes from CoinGlass: one value per day, going back to 2017. Our server loads the full history, keeps it for 30 minutes, and works out the rest from it. The page says it refreshes every 30 to 60 minutes, and the page itself is rebuilt at least once an hour. Because the source gives one value per day, the number does not move tick by tick.

Indexes of this kind usually count how many of the largest altcoins have beaten Bitcoin over a recent window, which is why they are slow to react. Check the CoinGlass source page if you need the exact recipe, as we do not republish it.

From that series we work out the zone for every day, the streak in the current zone, and the table of sustained altcoin seasons. A sustained season is a completed stretch of at least 14 days in a row in Altcoin Season. We chose the 14 days ourselves to filter out brief spikes. It is not an official definition. A gap of more than one day in the data breaks a stretch, so missing days never count towards a zone. The ongoing stretch is not counted as a finished season.

The CoinGlass index looks backwards. By the time it reads 75, a lot of the move has already happened. So below the chart we show two more readings that react differently. Both use CoinGecko market data and are cached for 24 hours, so they update once a day.

The ALT/BTC ratio is the total value of altcoins divided by the value of Bitcoin. Here altcoins means the whole crypto market minus Bitcoin, Ethereum and the main stablecoins. A rising ratio means altcoins are growing faster than Bitcoin. The page also shows an ALT/BTC risk score from 0 to 100, which blends our Risk Wave method with a percentile reading on the ratio. Below 30 is labelled low, 30 to 54 neutral, and 55 or more elevated.

BTC dominance is Bitcoin's share of the total crypto market, shown as a percentage. We compare today's level with its own history and give it a percentile. Below 35 is read as low relative to its own history, 35 to 64 as mid-range, and 65 or more as high. See the glossary entry on BTC dominance for the basics.

These three are combined into one line at the top of the panel. It counts how many of the available readings look favourable for altcoins: the index at 75 or higher, the ALT/BTC score below 30, and dominance in its low band. Two or three favourable gives Yes, one gives Mixed, and none gives No. If one reading cannot be loaded it drops out of the count. It is a simple tally, not a prediction.

Keep these in mind before you read anything into the number.

A made-up example. The index sits at 80 and has been in Altcoin Season for three weeks. The ALT/BTC risk score is 62, which is labelled elevated, and BTC dominance is in its neutral band. The tally reads one favourable reading out of three, so the line says Mixed.

That combination tells you the confirmation is there but the other two readings do not agree. It is a reason to look closer, for instance at the Altcoin Rules score, rather than a reason to act. The page gave you context. It did not tell you what to do.

This explainer and the Altcoin Season Index page are free to read for everyone. You do not need to log in, and in the code the page has no Premium gate: the chart, the table of past seasons, the ALT/BTC reading and the BTC dominance reading are all visible to every visitor.

Premium sits next to this page, not inside it. The closest related feature is the Altcoin Rules score, where free members can check a limited number of coins and Premium members can analyse unlimited coins. What is included changes over time, so check pricing for the current list.