The Altcoin season begins when most altcoins outperform Bitcoin. Currently, we do not have a true Altcoin season, according to the Altcoin Season Index. This index measures the performance of the top 100 altcoins compared to Bitcoin over the last 90 days.

According to Blockchaincenter, the Altcoin Season Index indicates that we are now in a "Bitcoin season" and not an Altcoin season, as altcoins have not sufficiently outperformed Bitcoin. An Altcoin season requires that 75% of the top 50 altcoins perform better than Bitcoin during the season ¹.

You can follow the Altcoin Season Index on sites like CoinMarketCap and Blockchaincenter to keep up with the latest developments in the cryptocurrency market ² ¹.