Translation:Before raining, the sky is clouding up.
Agreed. It seems like the last few skills in the tree have not been reviewed by a native English speaker.
Gets cloudy would of course be fine. Clouds over is widely used / understood in England. I've rechecked since last posting that it wasn't just a family thing that had got lodged in my old brain, and for further confirmation see: https://dictionary.cambridge.org/dictionary/english/cloud-over
A înnora ..... get cloudy
Nor - nori. .... cloud-clouds
Norul - norii. ..... defined