Is where they would be protected from the wind a noun clause?

Yes, "where they would be protected from the wind" is a noun clause.

Here's why:

* It functions as a noun: It acts as the object of the preposition "where". The entire phrase answers the question "Where would they be?".

* It contains a subject and a verb: "they" is the subject, and "would be" is the verb.

* It expresses a complete thought: It describes a place where they would be protected from the wind.

Therefore, "where they would be protected from the wind" meets all the criteria of a noun clause.