A ZIP+4 code uses the basic 02119 Zip code plus four additional digits to identify a geographic segment within the five-digit delivery area, such as a Roxbury city block, a group of apartments, an individual high-volume receiver of mail or any other unit that could use an extra identifier to aid in efficient mail sorting and delivery in Massachusetts.
A proper noun is different from a pronoun. Days of the week are always capitalized and are proper nouns. Names of cities and names of people are proper nouns. Pronouns are words like he, she, it, you, yours. Yes, the days of the week are proper nouns and always capitalized. Pronouns are a class of words used to refer to other specific nouns. The most common English pronouns include he, she, it, me, I, us, we, you, they and them. If you capitalize it in the middle of a sentence, it's (generally) a proper noun.
The first part seems to be trivial. Names of months and days of week (DoW) are proper nouns since they are dedicated to certain deities: Roman for months and Norse for DoW. So they are capitalized as any proper names. September to December are proper nouns as well for unification reasons, AFAIU. As per seasons, this question at EL&U seems to be relevant. Quoted: 1  The four seasons are lowercased. 2  Except when part of a formal name, such as the name of an event (Winter Olympics), school term (Spring Quarter 2012), or issue of a journal (Summer 2008). 3  Except when the season is personified, as in poetry.