The transition is just a few minutes. In English they usually call it dusk or gloaming, in Hungarian we say “szürkület” which refers to the grey color. During the summer its usually around 9pm or later, in December this moment arrives around 4pm. Nowdays since we are closing to the spring……ok, la! (Chinese effect in my speech):) I am optimistic!….so nowdays this dusk comes around 5pm.