What Is the Altcoin Season Index? June Could Be the Prelude to Altcoin Season

In the cyclical rotation of the crypto market, the altcoin season has always been the focus of investors. The core indicator measuring this trend, the alt season index, has recently shown key changes, providing important signals for a market turnaround in mid-2025.

What is the Altcoin Season Index?

This index tracks the performance of the top 100 alts (excluding stablecoins and wrapped tokens) over the past 90 days to see if they have outperformed Bitcoin (BTC). The criteria for judgment are clear:

• ≥ 75: Mark the beginning of “alt season” (over 75% of alts outperform BTC)
• ≤ 25: In the “Bitcoin season” (BTC dominates the market)
• Median: Considered as a “neutral zone”, indicating that capital rotation may be approaching.

In March 2025, the index fell to 13.1, the lowest since the summer of 2024, as the market was deeply trapped in the “Bitcoin season.” By mid-June, the index rose to 23, breaking through the Bitcoin range and entering the neutral zone, signaling an early transformation.

Current Index Position and Trend: The Game in the Neutral Zone

• Historical Similarity: Research institution Alphractal points out that starting from June 2022, there has been a pattern of increased momentum for alts every June. In June 2025, the index is expected to rise again, with 23% of alts outperforming Bitcoin on a daily basis, echoing seasonal trends.
• Signs of Bitcoin fatigue: BTC’s increase this month is only 1.42% (current price around $105,000), while some small-cap tokens like $GOUT and $MEV have surged significantly, indicating that funds are beginning to tentatively shift towards higher-risk assets.
• Threshold not reached: Although the index has moved away from “Bitcoin season”, it is still far from the “alt season” standard of 75, indicating that the market is still in a transitional phase rather than a full-blown explosion.

Key Evidence Supporting the Upcoming Alt Season

The Strong Foundation of Ethereum Ecosystem and Layer 2

• Ethereum Layer 2 networks (such as Base) have surpassed 500 TPS, with an annual growth exceeding 36%, significantly reducing transaction costs and enhancing security.
• High throughput provides infrastructure support for DeFi, NFT, and gaming alt projects, driving user activity and on-chain demand, creating the soil for the explosion of alts.

Stablecoin Liquidity “Fuel”

• The total market capitalization of stablecoins has reached $255 billion, with U.S. compliant stablecoins growing by 104% year-over-year, and non-U.S. stablecoins growing by 41%.
• A massive amount of stablecoins represents off-exchange funds waiting for action; once sentiment shifts, they can quickly convert into altcoin purchasing power, catalyzing upward trends.

ETH/BTC Exchange Rate Trend Reversal

• The ETH/BTC trading pair has ended a 669-day downtrend, with weekly support forming. The technical pattern is similar to early 2020, after which a 20-month altcoin bull market cycle began.

Key Contradiction: Bitcoin strength remains the biggest variable

Despite the accumulation of momentum in alts, Bitcoin’s strong performance still exerts pressure.

• Bitcoin’s weekly increase is 11%, and its monthly increase is 26%, trading at a high of $105,000, significantly raising the benchmark.
• If Bitcoin’s dominance (BTC.D) does not fall below 50%, it may be difficult for funds to pour into alts on a large scale.

Investor Strategy: Monitoring Indicators and Layout Suggestions

• Focus on the index threshold: If the Altcoin Season Index breaks above 50 and continues to rise, it can be seen as a significant increase in the probability of an alt season.
• Pay attention to related indicators: including the number of active Ethereum addresses, stablecoin inflow, ETH/BTC exchange rate strength, etc.
• Sector rotation prediction: AI track tokens (such as RNDR, AGIX) and Ethereum ecosystem tokens (related to L2) have recently shown higher sensitivity and can serve as a barometer.

Conclusion

The alt season index is breaking away from the “Bitcoin gravitational zone,” with Layer 2 adoption rates, stablecoin liquidity, and ETH strength forming a triangular support. If historical cycles repeat, June 2025 may herald a new round of altcoin market activity. However, whether Bitcoin will willingly cede its position still needs to be observed for any substantial shifts in its dominance. Investors should use the index as a guide to capture structural opportunities amid rotations.