Been thinking about how capital actually moves in crypto, and honestly, it's not random at all. There's this pattern everyone talks about but not everyone really understands — the shift between Bitcoin dominance and what we call altcoin season.

So here's the thing: the Altcoin Season Index is basically your radar for this shift. It measures how the top 100 altcoins are performing against Bitcoin over a 90-day window, and it gives you a simple 0-100 score that tells you where the market's actually headed.

The framework is pretty clean: 0-25 means Bitcoin's in control, altcoins are sleeping. 25-75 is neutral, no clear winner. Then 75-100 — that's when altcoin season really kicks in and capital starts flowing into everything from Ethereum to the smaller cap projects.

What makes this work is the underlying logic. When 75% or more of those top 100 altcoins start outperforming Bitcoin, the index signals it's altcoin season. That's not just a number on a chart — it's actual capital rotation happening in real time.

Why does this matter for trading? During altcoin season, you're looking at XRP, mid-cap projects, lower-cap coins all moving faster than Bitcoin. The volatility is higher, which means the opportunities are bigger if you time it right. During Bitcoin season, it's the opposite — you're managing risk, maybe rotating into stables or just holding Bitcoin itself.

I use the altcoin season index alongside other tools like RSI and the Fear & Greed Index to get a fuller picture. It's not a crystal ball, but it's surprisingly effective for positioning. When I see the index climbing toward that 75 mark, I know capital's starting to rotate. That's when I'm thinking about adjusting my portfolio allocation.

One thing to remember though: the index shows you market-wide trends, not individual coin performance. Just because we're in altcoin season doesn't mean every altcoin moons. Some still underperform. And external stuff — news, liquidity issues, macro events — can flip things fast.

But if you're serious about understanding market cycles, the altcoin season index is one of those tools that actually gives you an edge. It's not about predicting the future, it's about reading where capital is flowing right now and positioning accordingly. In crypto, that's usually enough to stay ahead of the curve.