The onset of altseason — a period when altcoins show higher returns compared to Bitcoin — is determined by a number of key indicators. Here are the main indicators and on-chain data that signal its beginning:
📊 1. Altcoin Season Index
· A value above 75 is the main criterion. The index is calculated based on the comparison of the performance of the top 50 or top 100 altcoins against Bitcoin over the past 90 days. If more than 75% of altcoins outperform BTC in growth, it is considered the beginning of altseason.
· Example: As of September 2025, the index reached 78, indicating an active phase of altseason.
📉 2. Decrease in Bitcoin dominance (Bitcoin Dominance)
· Falling below 55-57%. The share of Bitcoin in the total market capitalization of the crypto market decreases, indicating a capital outflow to altcoins. For example, in September 2025, Bitcoin dominance fell to 57.4%.
· Breaking key support levels. For example, in 2025, Bitcoin dominance broke the support of the downward channel, signaling weakness in Bitcoin and potential for altcoin growth.
📈 3. Growth of altcoin capitalization
· The capitalization of the altcoin sector exceeds $1.8 trillion and approaches historical highs. This indicates a massive inflow of investments into altcoins.
· Acceleration of growth relative to BTC. For example, Ethereum showed a growth of 19% in August 2025, while Bitcoin fell by 6.5%.
🔍 4. Technical indicators and market dynamics
· Bearish signals for BTC. The weekly chart of Bitcoin dominance shows a bearish MACD crossover and a failed retest of resistance, which could lead to a decline to 42-44%.
· Bullish patterns in altcoins. For example, Avalanche (AVAX) is consolidating in a symmetrical triangle with the potential breakout to $50.
⛓️ 5. On-chain data and network activity
· Growth of on-chain activity. An increase in the number of daily transactions and active addresses in altcoin networks. For example, in Avalanche, the number of daily active addresses increased by 57%.
· Decrease in balances on exchanges. For example, Ethereum balances on exchanges are decreasing, indicating accumulation and reduced selling pressure.
· Records in DeFi and DEX. The volume of decentralized trading (DEX) reached 30% of the total spot trading volume, while the volume of DeFi lending reached $70 billion.
💹 6. Institutional interest and macroeconomic factors
· Inflow of funds into ETFs. For example, Ethereum ETFs attracted $29 billion, while corporate treasuries accumulated tokens worth over $21 billion.
· Macroeconomic conditions. Easing of monetary policy (quantitative easing) or delay in introducing regulatory barriers (for example, tariffs) can stimulate the inflow of liquidity into risky assets such as altcoins.
🧠 7. Market sentiments and investor behavior
· Shift towards risky strategies. Traders begin to invest more actively in altcoins, which is reflected in the increase of the fear and greed index for specific projects.
· Hype around meme coins and new projects. For example, XYZVerse showed growth due to a deflationary model and gamified engagement.
💎 Conclusion
Altseason usually starts with a combination of several factors: the altcoin season index exceeds 75, Bitcoin dominance declines, and altcoin capitalization increases. On-chain data, such as network activity and the reduction of balances on exchanges, confirm the capital flow. However, it is important to remember that the current market cycle may differ from previous ones — growth may be concentrated in specific sectors (for example, AI or meme coins), rather than across the entire altcoin market.
To make decisions, it is recommended to track several indicators simultaneously and consider the macroeconomic context.
Is not an individual investment recommendation