When Will Altcoin Season Start in 2026?

The altcoin market has remained weak against Bitcoin for years, but one analyst believes the conditions for a new altcoin season could finally be forming. His analysis points to the U.S. ISM manufacturing index, Bitcoin momentum and improving Asian export data as key signals to watch.

Altcoins Have Been Weak Against Bitcoin

The current cycle has looked very different from 2017 and 2021. In 2017, Bitcoin dominance fell from around 95% to 35%, while in 2021 it dropped from roughly 73% to 39% as capital rotated heavily into altcoins.

By comparison, Bitcoin dominance fell only from around 66% to 57% in 2025. This created a much smaller window for altcoins to outperform Bitcoin and prevented the broad-based rally seen during earlier cycles.

“The ISM Is the Key Trigger”

The U.S. ISM manufacturing index could be one of the most important signs for the next altcoin cycle. Historically, stronger manufacturing activity has coincided with altcoins outperforming Bitcoin.

The crucial level is 58. When the ISM moved above that level in 2017 and again around 2020, the Others-vs-Bitcoin metric surged while Bitcoin dominance fell sharply.

Since 2021, the ISM has largely remained below 50, reflecting weaker manufacturing conditions. This prolonged weakness coincided with altcoins continuing to underperform Bitcoin.

Bitcoin has remained relatively resilient despite geopolitical tensions, high oil prices, corporate selling and a recent $130 million cold-wallet hack. This could indicate that selling pressure is becoming exhausted and buyers are gradually returning.

The House of Crypto also points to September–October as a potential altcoin window if the ISM manufacturing index reaches 58. 

Early Clues!

South Korean exports and Taiwan export prices are also important because both economies are major suppliers of semiconductors and technology components.

Recent strength in these indicators could improving global manufacturing demand ahead of the ISM data. If that momentum continues, the ISM could eventually move toward the 58 level that previously coincided with major altcoin rotations.

Which Altcoins Could Benefit?

If Bitcoin begins to stall while the broader market improves, the strongest altcoins could be among the first to move. Michaël van de Poppe sees Ethereum (ETH) and Solana (SOL) as key names to watch, saying strong altcoins could break higher once Bitcoin pauses. 

Meanwhile, another analyst says the broader altcoin market’s $161 billion market cap is sitting near the $160-$165 billion support zone, with a deeper support level around $124 billion and a potential upside toward $320-$340 billion if the current base holds. 

Within individual projects, Pump.fun, Hyperliquid and Morpho stand out for their revenue, network activity and token-related mechanisms. 

Overall, the analysts are focusing on fundamentally stronger altcoins rather than expecting the entire market to rally at once.