In Polish we place „nie” just before the thing we want to negate. „X to Y” expressions are however special and one can only place nie in one place, namely like that: „X to nie Y”.
If we had proper sentence: „Listopad nie jest tygodniem” or „Listopad jest nie-tygodniem”. That are two possibilities, that have slightly different meaning. The first corresponds to English „November is not a week.”. The latter is: „November is a not-month” - (November is a member of a group consisted of entities that aren't months”.