Recently, someone asked me what alt season is, and this topic is indeed worth a deep discussion. In simple terms, alt season is the period when Bitcoin is rising, but its market share is actually decreasing—in other words, a phase when other coins perform better than BTC.

I looked through historical data and found that in the entire history of the crypto market, we have only experienced two true global altcoin seasons. The first was in 2017, starting from March 1st, when BTC’s dominance dropped from 96% to 36%, and the total market cap of altcoins (TOTAL2) skyrocketed from less than $1 billion to $470 billion. This rally lasted 310 days, with a growth of 564 times. Crazy, right?

The second alt season occurred during the 2020-2021 cycle. It started on January 3rd, 2021, with TOTAL2 jumping from $225 billion, reaching its peak in November 2021. This lasted 309 days, with an increase of $1.5 trillion, a 6.5x rise. Interestingly, both alt seasons lasted almost exactly the same—about 310 days. Coincidence? I think not.

I noticed a deeper pattern: both alt seasons are clearly linked to Bitcoin halving events. After the 2016 halving in July, the first alt season started 235 days later (March 2017). After the 2020 halving in May, the second started 237 days later (January 2021). The time gap is almost identical.

Based on this pattern, we can infer a cycle. If this rule continues to hold, then after the 2024 halving on April 19th, adding 235 days, we might see the next alt season signal around December 10th. Plus, considering the typical 310-day cycle, the entire alt season should end around mid-October 2025—that also aligns with our previous prediction for the cycle’s top.

Now, in mid-2026, looking back, these predictions have basically been validated. Alt season indeed unfolds according to historical patterns, with strong projects continuing to dominate the market. Data shows that the best-performing coins in the last cycle experienced parabolic gains during alt season. This tells us one thing: instead of chasing dark horses, it’s better to focus on top projects that have already proven their strength.

Regarding which coins might benefit most from this round of alt season, I see good performance from AI, blockchain infrastructure, and some established mainstream coins. Of course, if you’ve looked at this year’s top gainers, you’ll notice meme coins also performed quite well, but that’s mostly driven by sentiment.

To sum up some core questions about alt season: When does it start? About 235 days after the halving. How long does it last? According to historical patterns, around 310 days. Which coins will rise the most? Usually those that are already strong, not obscure new projects. That’s the logic of alt season—the strong get stronger, and cycles follow a pattern.