Short Answer: Part of speech tags can not be used to determine temporal prepositions.
Long Answer: If you really want to do this, extract the prepositional phrases, and run those phrases through 'prepositional sense disambiguation' system. They will use a combination of the preposition plus the object of the preposition to determine if the PP was indeed being used to indicate a temporal notion.
UPDATE: Also see the book, "Neural Networks for Natural Language Processing" by Yoav Goldberg. Chapter 7.6 walks the reader through the detailed steps of preposition sense disambiguation.