The school picnic is on Sunday, so we're praying for a fine day.

星期日学校要组郊游野餐, 我们非常希望那天是个风和日丽的晴天。

The morning began fine, but now clouds are banking up.

早晨开始是晴天, 可是现在乌云密布。

Wet days alternate with fine days.

雨天和晴天相间来。

On a bright and clear day a 15-cm helio can be seen at 50 km .

在朗的晴天，15厘米大小的回照光在50公里处能看到。

The papers forecast clear skies tomorrow.

报纸预报天晴天。

Rain or shine, I'll go.

不管下雨还是晴天, 我都要去。