第二天天亮了，万里无云，天朗气清。

The next day dawned cloudless and fair.

youdao

万里无云，湛蓝的天空俯视着他们，风把夜晚的每一片云彩都吹走了。

A cloudless, deep-blue sky looked down on them, for the wind had driven away every little cloud in the night.

youdao

万里无云。

There are no clouds in the sky.

《新英汉大辞典》

Great battle, it's got to have sunshine, blue skies, terrific--well, never mind.

伟大的战争,一定要阳光普照,万里无云,--我扯这些干什么

耶鲁公开课 - 古希腊历史简介课程节选