The day dawned sunless and with a low cloud base.
黎明时天气阴沉，云层压得很低。
Fog and low cloud cover are expected this afternoon.
预计今天下午有雾和低空云层。
The moon was fuller than the night before, but the light was diffused by cloud.
月亮比头一天晚上更圆，但因云层遮掩而月光朦胧。
The wind has changed direction.
风向已经变了。
Wind speeds reached force five.
风速达到了5级。