Why are some vegetables delicious and some not delicious in winter?

Why are vegetables especially delicious in winter? It turns out that in the weather below the first frost of 4℃, Chinese cabbage will be frozen, the cell membrane will rupture, and substances such as sugar and amino acids in the cells will also ooze out, forming a sweet, soft and attractive taste. However, before the first frost, the Caicai handle of Youdong was hard in taste and easy to lose slag. Actually, it's not delicious, and it's a little bitter.