getting dark, darkening
Está escurecendo cada vez mais.
It's getting darker and darker.
Não deveria estar escurecendo agora?
Shouldn't it be getting dark now?
— Os Mortos Não Morrem (2019)
The sky is darkening.
It's getting dark outside.
Já estava escurecendo quando cheguei.
It was already getting dark when I arrived.
The clouds are darkening.
Estava escurecendo e, para piorar, começou a chover.
It was getting dark and, to make matters worse, it started to rain.
It was getting dark.