"vacations" - plural - in english means at least two vacations. like "I went on two vacations last year."
in spanish, isn't "vacaciones" always plural? for instance, don't you say "me gusta mis vacaciones" to mean "I like my vacation."
my reply of "Vacation is in November" should be correct as I'm fairly sure "las vacaciones son en noviembre" is not meant to refer to the fact that "VacationS are in November." even if I went with my family of 10 people in November, it would still be "vacation is in november."
Don't be confused by word for word substitution. “Las vacaciones" is indeed always in the plural form. The difference is not in how many vacations you are taking, but rather that you always use the plural form for vacation when speaking in Spanish, whether you are taking what would be considered one, two, or ten vacations in English. It doesn't make sense from an English perspective, but it isn't English.