Questions & Answers about W wakacje chodzę spać później niż w tygodniu.
Yes. Wakacje is normally a plural-only noun in Polish, meaning summer holidays / vacation.
So Polish says:
- wakacje są długie = the summer holidays are long
- w wakacje = during the summer holidays
This is similar to English holidays, though English also has singular vacation, while standard Polish usually uses plural wakacje for this idea.
Both can be possible, but they are not exactly the same in feel.
- w wakacje = during the holiday period / in the summer holidays
- na wakacjach = on holiday / away on vacation
In your sentence, w wakacje chodzę spać później sounds like a general statement about your routine during the summer break.
By contrast:
- Na wakacjach chodzę spać później often sounds more like when I’m on vacation.
So w wakacje is a very natural choice when talking about habits in the holiday season as a time period.