Structure of days of the week

Days of the week are just numbered: 星期一 is Monday, straight through to 星期六.

星期 + Number (星期天 for Sunday)

How it works

Monday through Saturday are 星期一 to 星期六. Sunday breaks the pattern — it is 星期天 or 星期日, never 星期七.

周 and 礼拜 are common alternatives to 星期 (周一, 礼拜一) and behave identically. To ask which day it is, use 几: 今天星期几?

Note that no verb is needed: 今天星期三 is a complete sentence.