Weather is rain, wind, and temperature. Whether introduces two possibilities. They are not interchangeable. Bad weather delayed the test. Whether to stay or go. This is a spelling trap, not the if-versus-whether rule in if versus whether.
Climate versus choice
If the sentence is about the sky, use weather. If it is about alternatives, use whether. The weather she applies is never right.
Diction overall is in word choice. Then versus than is in then versus than. Grammar overall is in ACT grammar rules.
The bottom line
Sky: weather. Two options: whether.
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