bardzo pochmurny in English:

The sky is overcast today.

It will be cold and the sky will be overcast.

It's been overcast for the past few days.

All of a sudden the sky became overcast.

The sky has become overcast.

an overcast day

But, even if it’s overcast, it’s just the white blanket everywhere and it’s still and if you are snowshoeing and you can get off the trail, you are in the woods with nobody around.

The sky/weather was overcast

For three days it was overcast.

The sky is overcast we are expecting it to rain later.

The night was dark and overcast.

to become overcast

The sky is overcast

The sky's a bit overcast.

Scarcely had we started out before the sky became overcast and down came the rain again.