"The weather is very windy today."

[bumfchert]

why doesn't "Hava çok rüzgarlı bugün" work?

[Samiwise]

As a Turkish,I use both of them,we all do :)

[mizinamo]

Duolingo almost always uses "standard" word order, with the predicate at the end.

The predicate is usually a verb but could also be an adjective or noun such as "rüzgarlı" that describes what or how the subject is.

So regardless of what people say on the street, for Duolingo, it's better to stick to a bit more conservative word order :)