Serein (/srin/; (s) in French) refers to rain falling from a cloudless sky. This sort of rain is said to take on the form of a fine, light drizzle, typically after dusk. The name derives from French serein, meaning ''serene'', or ''clear'' (as in unclouded). An alternative etymology is from Old French serain, evening.
Based on the above text, what's the best answer to this question: can it rain without clouds in the sky?
yes