"covered with clouds" is correct and usable in written English.
You can use it to describe a sky that is completely filled with clouds, like in the following example: "The sky was a pale grey, completely covered with clouds."
The prominent peaks are covered with clouds throughout the year and with ice in winter.
I decided to make the Ukrainian series in May, when the sky is mostly covered with clouds.
However, in June, the rainy season begins, and the sky over the island is covered with clouds.
Jupiter is perpetually covered with clouds composed of ammonia crystals and possibly ammonium hydrosulfide.
Like for example, when the sun gets covered with clouds and the sky becomes incredibly dark - the sun is still there, it didn't disappear, it's just covered up.
Weather depiction plots show ceiling height (level where at least half the sky is covered with clouds) in hundreds of feet, present weather, and cloud cover.
For two nights running, from the very comfortable, well-provisioned bar of the Volcano Lodge -- even from the terrace of our well-situated room -- we watched Arenal, when it was not covered with cloud, fume and glow with earth's fire, roaring like a fiend.
However, both primary and secondary targets were covered with cloud and the bombers attacked two convoys off the Frisian Islands.
The upper clouds cover wide areas, and parts of the left and right sides of the figures are covered with thick clouds.
The planet looks white because it's covered with thick clouds of sulphuric acid suspended in an atmosphere that's 96.5% carbon dioxide.
Venus is covered with thick clouds.
