There has been a period of settled weather.

曾有一段时期天气很稳定。

《柯林斯英汉双解大词典》

The weather has settled at last.

天气最后总算稳定了下来。

youdao

When the weather is fair and settled, they are clothed in blue and purple, and print their bold outlines on the clear evening sky.

在持续晴天的日子里，它们披上蓝紫相间的衣衫，把雄浑的轮廓印在傍晚清澄的天空上。 收藏。

youdao

The longest spells of settled weather occur during calm but cold days in winter.

BBC: Czech Republic

As elsewhere on the coasts of the southern Mediterranean, winter weather can be changeable from day to day with cool, cloudy, rainy spells interrupting the generally warm, sunny, and settled weather.

BBC: Libya

There's a very high chance of dry, settled nocturnal weather between now and Sunday night, with some local mistiness by dawn.

BBC: Glastonbury Festival 2010 weather forecast