Altcoin Momentum Builds as Glassnode Index Reaches 75, but Full Season Remains Uncertain

Glassnode’s latest data reveals a notable uptick in altcoin momentum as of September 2026, with the firm’s Altcoin Cycle Signal climbing to 75. However, broader market indicators present a more cautious picture, suggesting that while conditions are favoring altcoins, a sustained “altcoin season” is not yet confirmed.

Glassnode’s Altcoin Cycle Signal

Glassnode’s Altcoin Cycle Signal, which tracks the performance of the top 250 altcoins excluding stablecoins, rose to 75 in late August. The signal indicates that market conditions have shifted toward an altcoin-favoring phase. Yet, Glassnode’s September 15 Market Compass report cautioned that the rally that drove this reading subsequently faded, warning that simultaneous gains across assets can occur during riskier market phases.

Mixed Signals from Broader Indicators

Another widely followed measure, BlockchainCenter’s Altcoin Season Index, stood at just 53 on September 22, well below the 75 threshold typically used to define an altcoin season. This index measures how many of the top 50 cryptocurrencies have outperformed Bitcoin over the previous 90 days. The divergence between the two indices highlights an important dynamic: altcoins can rise in dollar terms without necessarily outperforming Bitcoin. Glassnode acknowledged this in its September research, noting that while altcoin market capitalization increased, altcoins had not yet taken meaningful market share from Bitcoin.

Bitcoin Remains a Key Driver

Bitcoin’s performance remains crucial for any broader rotation. Glassnode’s recent analysis shows Bitcoin consolidating after a period of gains, with capital flows and derivatives activity continuing to influence market direction. For a more established altcoin rotation, market participants will likely watch Bitcoin dominance, relative altcoin performance, and trading breadth. A sustained improvement across these indicators would provide stronger evidence of a broad-based shift.

Outlook for a 2026 Altcoin Season

The market appears to be in a transition phase. Whether this develops into a sustained altcoin season in 2026 will depend on whether altcoins can continue outperforming Bitcoin over a longer period. Until then, investors should approach the current momentum with caution, as the signals remain mixed.