It's getting dark

It's getting dark
 

It´s getting dark = está anocheciendo
what about está amaneciendo = it´s getting bright ???? Or just it´s daylight or the day is starting?

It´s getting light, I saw it in the dic.

To dawn
Although this also means to (sometimes gradually) understand.
' Eventually it dawned on me that he wasn't going to help me at all'.
' Listening to the wolves howling in the woods, it dawned on us that we were not safe and needed to find shelter for the night'.

Besides dawn which when used literally means el amanecer, we use sunrise or sun up.

Está amaneciendo.
It's getting light.
The sun's coming up.
It's dawning.