The pronoun 'you' can be used both as a singular and a plural pronoun. However, it is never paired with 'is' and always with 'are'.
Why is it that 'you' is considered plural?
My guess would be that it has something to do with its etymology: perhaps it was derived from a plural form which is why it remains so to this day. However, if anyone has any further clarification that would be greatly helpful.