Altcoin season signal flips as majors rally

TLDR

Altcoin season indicators are starting to flip as Bitcoins rally broadens into large-cap altcoins, but the rotation is still early rather than full blown.

1. Glassnodes Altcoin Cycle Signal has moved into altcoin season territory, with altcoins combined market cap up and Bitcoin dominance stuck below 60 percent.
2. Majors like Ethereum (ETH), Solana (SOL), XRP, Dogecoin (DOGE), Cardano (ADA) and Sui (SUI) are now outperforming Bitcoin in the latest leg of the rally.
3. Sustained altcoin season depends on breadth beyond majors, Bitcoin dominance trends and ETF flows, with short squeeze and leverage risk still significant.

Deep Dive

1. Altcoin Season Metrics Flip

Onchain analytics firm Glassnode reports its Altcoin Cycle Signal has flipped from Bitcoin season to altcoin season, with the seven day average around 81 on a 0 to 100 scale, above its altseason threshold of 75. The metric compares Bitcoin to a market cap weighted basket of 250 altcoins excluding stablecoins and currently favors altcoin outperformance, while Bitcoin dominance has stalled below 60 percent according to Cointelegraph.

Glassnode notes that an earlier August rally was almost entirely Bitcoin led, but the latest move above 86,000 dollars has ignited the full breadth of the altcoin market as total altcoin cap reached about 1.19 trillion dollars and the overall crypto market reclaimed roughly 3 trillion dollars.

CoinMarketCaps own Altcoin Season Index sits around 51 out of 100, up from the low 30s a week ago, which confirms increasing rotation but not yet an extreme altseason regime.

2. Majors Lead The Rotation

Newsflow shows large caps now gaining faster than BTC. In the past 24 hours, DOGE, SUI, XRP, ADA and SOL posted gains between roughly 4 to 12 percent, while Bitcoins move in the same window was only a bit over 2 percent.

Earlier coverage highlighted ETH breaking higher with double digit moves, alongside BNB, XRP and DOGE, as Bitcoin pushed through 87,000 dollars, signaling that the rally is no longer confined to the single largest asset and that capital is starting to seek higher beta names.

At the same time, ETF flows into both Bitcoin and Ether have surged to their strongest daily levels since late 2025, reinforcing institutional interest in majors rather than just speculative small caps.

3. Signals And Risks To Watch

Other gauges are more cautious. Blockchaincenters Altcoin Season Index was around 41 on September 20, well below its 75 altseason line, suggesting that many altcoins have recovered against the dollar but still lag Bitcoin over a ninety day lookback.

Key things to monitor are 1) breadth of gains across mid and smaller caps, not just the top 20 coins, 2) Bitcoin dominance drifting down from the high 50 percent zone, and 3) whether ETF inflows stay strong or reverse. High open interest and recent short squeezes also mean the move could retrace quickly if sentiment or macro conditions turn.

Conclusion

Altcoin season signals have clearly shifted toward altcoin outperformance as Bitcoins breakout above 86,000 dollars starts to pull majors higher, but indicator levels and dominance data show the rotation is still developing. If breadth expands beyond large caps while Bitcoin dominance drifts lower and ETF demand remains firm, this phase could evolve into a more classic altseason rather than a brief, squeeze driven burst.