For me, 'on the weekend' usually implies the future, referring to something that is about to occur: "Come visit me on the weekend. I'll be here." If talking about something that has passed, I'd say "Last weekend I . . . ' "on weekends" refers to something that happens habitually: "On weekends, I usually sleep in."

'on the weekend' could refer specifically to the most recent weekend. A general enquiry would more likely use 'on/at weekends', meaning any weekend, not just the next/last one.

In the example sentence, they mean the same thing. In general, "on the weekend" or "over the weekend" will stress the fact that your weekend behavior is different from your weekday behavior.

I think so. Thank you.

Hi Wang, If talking about something that happens multiple times or frequently, you can use both of those phrases and both sound native. But if talking about something that happened one time or if you do one time, you should use "on the weekend". It was my birthday on the weekend. I went to a wedding on the weekend. Want to go running on the weekend with me? Things that happen often or you do many times, you can use either. I usually play piano on the weekend/on weekends. I watch movies on the weekend/on weekends. I am very busy so I can't see you on the weekend/on weekends.