Winter break can be capitalized, or lower case. If, on a calendar, you are writing winter break, then you would put "Winter Break". On anything else, it could be "winter break", "Winter break", or "Winter Break".
no but its not good to be left out
You do not captitalize "science", but you should capitalize when it's in the form of "Science 30".
Not cover but try to protect from heavy weight of snow as it can break branches.
Probably since it's a chemical name, I capitalize Oxygen when I say it.
no you do not
no
yes
No, "winter festival celebration" should not be capitalized unless it is part of a title or at the beginning of a sentence.
YOU CAPITALIZE THINGS LIKE SPRING, SUMMER, AND WINTER WHEN YOU USE PERSONIFICATION.FOR EXAMPLE, As I was walking down the street, Winter came and blew away my hat.
No, it's not necessary.
There is no winter break in football.
Of course if u capitalize summer,spring,and Fall why don't u capitalize Winter 
I have a friend that is very restful.
336 hours are in a winter break.
Yes, you need to capitalize them.
No, the word "winter" should not be capitalized in the middle of a sentence unless it is at the beginning of a sentence or part of a proper noun.
the subject is break winter describes the reak is is the verb the break is doing the action of being