overcloud

The sky began to overcloud in the early afternoon, so we moved the picnic under the pavilion.

午后天空开始布满乌云，于是我们把野餐搬到凉亭下。

If the mountains overcloud before noon, the guide usually cancels the climb.

如果中午前山上乌云密布，向导通常会取消攀登。

The horizon had overclouded by sunset, and the fishermen expected a stormy night.

日落时地平线已经乌云密布，渔民们预料将有一个暴风雨之夜。