'Which is your favourite season' is probably better English. It should be accepted I think.
Not "better"--it just uses British English. I have added the U.K. spelling variant.
I may be wrong but I think Ronnie's point might be the use of "which" instead of "what", rather than about spelling.
I said which season do you prefer and think this is completely acceptable
I agree. This seems like a more direct translation.
Is quelle used because saison is feminine ? Would it be quel or quil if the noun were masculine? I got it right but just trying to understand why I got it right. Will appreciate some explanation/clarification. Thanks