I’ve seen some colleges that require a 1 year of arts courses taken during high school. Is it advisable to take 1 year of arts courses so I can fulfill this requirement? For those of you that are applying, does it really make a difference, and do you have an advantage over someone who hasn’t fulfilled this requirement?
It will make no difference. Unless it is an AP class you cannot fulfill a college core requirement with a HS class. It is not uncommon for HS students to take art classes so it will not help you to stand out-- in fact our HS (or it could be the state) requires one year of art/music for graduation. And many HS students take multiple music/art classes.
Our school only requires 1 trimester of arts. I think my original post wasn’t clear, I meant some colleges require 1 year of the arts to be admitted to the college.
California and South Dakota public universities require a year of high school art for frosh admission (although the California schools allow fulfillment by AP art scores or college art courses). It is possible that other schools also require or recommend high school art for frosh admission. So check each school that you are possibly interested in to see if such is required or recommended. If they do, and you do not have it, you may be auto-rejected (if art is a hard requirement) or be reviewed disadvantageously (if art is recommended) at such schools.
I agree with @ucbalumnus If you are applying to UC’s, it is a hard requirement. For colleges that do not have a hard requirement, it will be neither a positive nor a negative if you take a year of art.
Great, thanks for the advice 
I think I’ll take a year of art, I don’t mind if it’s not a requirement, but I don’t want to end up not taking it and then it’s a requirement.
Many hs do require 1 year of art class to graduate. If it is a music program like orchestra or band, it may need continuous effort (e.g. all 4 years) to make it useful for college application.