"Yes, I am busy on the weekends."
What I want to know is why you use は instead of に to signify that it is on the weekend.
According to another comment I read に isn't used for regular occurences like "every weekend" (or in this case, "weekends"). I also believe は is optionally used for emphasising the time; it accepted my translation of はい、週まついそがしいです。, which you may notice does not include the は.
that's annoying. I had the "are you busy on weekdays" question right before this and I used the wrong work :(
So this sounds like the answer to a question. So why is it はい instead of そう?
(Then again, a native speaker wouldn't say this in response to a question; they'd just say 「そうです」.