The most common and most likely answer to this crossword clue is the 5 letter word NIMBI
I've seen this crossword clue in The Guardian
N
I
M
B
I
More clues leading to the result NIMBI
- Instances of light above the blessed clouds!
- They may surround the head doctor introduced to new team
- IT company starting to invent new revolutionary clouds
- They might have rain in north — declaration after batting for both sides
- Clouds of gas? Setter’s big end’s gone
- Review of global IT firm in Sky features
- Sign of bad weather anything but locally in report?
- Clouds rising from Maghrib mines
- Clouds naturally impair most bright images at first
- Sources of water selfish protester cut before one
Buddy explains!

The straight part
We know that "Clouds" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case clouds = nimbi.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does NIMBI mean?
NIMBI noun- A circle of light; a halo.
- A gray rain cloud.