The phrase "leaden clouds" is correct and usable in written English.
It can be used to describe heavy, gray clouds that suggest a gloomy or oppressive atmosphere.
Example: "As the storm approached, the sky darkened with leaden clouds, casting a shadow over the landscape."
Alternatives: "heavy clouds" or "gray clouds."
For example, "Dying Buffalo in a Snowdrift" (1839) has appropriately leaden clouds in the sky.
He fell back into the field, and the leaden clouds, which had hovered ominously for 100 laps, finally let loose.
About a half-hour before the game, the leaden clouds had disappeared and playing left field became an adventure for Matsui.
Sometime in August the leaden clouds over the lineup parted, and we found ourselves with a sun-splashed contingent of conspicuously athletic young players — shortstop Xander Bogaerts, catcher Blake Swihart, outfielders Jackie Bradley, Jr., Rusney Castillo, and Mookie Betts.
On Monday, against the steep wall of the northern Rocky Mountains, their tops obscured by the leaden clouds that clung low to the valley throughout the day, relatives of the victims visited the crash site, which was in a cluster of blue spruce trees.
We head off, after a full British breakfast in the pub, under wide leaden clouds, winding back up the formidable face of green hillside, and make our first stop of the day at Fyfield Down, a vale studded with gorse, with ancient "strip lynchet" field terraces marking the land in italic lines.
Rainclouds are constantly obscuring the small patches of blue sky, and on this day a leaden cloud cover moved over us permanently.
Leaden grey clouds mass on the horizon and mist in the air blurs the outlines of ships in the distance.
Tempering the film's oppressive emotions, the cinematographer Zoë White's exquisite compositions charge leaden rain clouds and rustling branches with eerie life, and dusty indoor corners with shadowy secrets.
Sometimes, the only thing skiers and operators can do is look to the skies -- as they used to say in 1950s science fiction movies -- and wait for a bank of leaden snow clouds to roll their way.
Over the river a golden ray of sun came through the hosts of leaden rain clouds.
