The sky threatened rain any minute, and the hour was six-twenty-almost closing time.
Before the sun plowed through the clouds at the last minute, the skies threatened a big rain.
The sky threatened rain and it had become suddenly dark.
The skies threatened rain during the day but none fell.
The blizzard had passed but the sky threatened more.
The sky threatened rain for the night, probably another steam-bath fog tomorrow.
The sky was threatening; there'd be rain before sunset, she supposed.
Then the sky threatened for a day, and after that they plodded in the rain.
The sky did not so much promise as threaten more precipitation.
The snow was no longer falling but the sky threatened more to come.