So currently we're not yet in the altcoin season as obviously bitcoin is still dominating. And almost all altcoin are still way below their previous all time high although Ethereum already break the 4 digits barrier but it need as a lot of money to even break $1400, its all time high.
Some altcoins are rising too much in recent weeks but you are right that it is not an altcoin season as not most of altcoins are rising. They rise next-by-next and don't rise at the same day or week.
Moreover, they are rising mainly in their price with USDT, not rising much in BTC. A few altcoins have doubled or trippled their price in BTC and more increases in USDT as price of Bitcoin in USDT is still rising. The altcoin season will only come when people feel safe with bitcoin, don't see bubble burst with bitcoin, then bitcoin is stable price for a while and altcoins might rise all together.