Breaking down a sentence and an attribute clause

Question

Frost's Descent is the last solar term of autumn, during which time the weather becomes much colder than before and frost begins to appear.

"during which = when" introduce an attributive clause “time the weather becomes much colder than before and frost begins to appear.” What followed after "when/where/why" in an attributive clause is a completely sentence, however, "time the weather becomes much colder than before and frost begins to appear" - the subject is "the weather", the predicate is "becomes", the object is "much colder than before"...What component of "time" in this sentence?

Answer 1

"Which" can serve as a pronoun referring to something else or as an adjective specifying a noun. The difference is analogous to the difference between saying "That was fun" and "That ride was fun". In this case, the phrase used to introduce the clause is "during which time", and the whole phrase functions like "when", specifying that late solar term is the period in which the weather becomes colder.