星期【xīngqī】

The days of the week are 星期 plus a number, counting from Monday.

星期一 Monday, 星期二 Tuesday, 星期三 Wednesday, 星期四 Thursday, 星期五 Friday, 星期六 Saturday.

To ask, jī几 takes the place of the number.

Sunday breaks the pattern

Sunday is Xīng qī tiān星期天 in speech and Xīng qī rì星期日 in writing. There is no seventh number.

• × 星期七 → 星期天

是 is optional

A day takes no verb: 今天星期三 and 今天是星期三 are both normal. The negative does need 是.

Last week, this week, next week

shàng gè xīng qī上个星期, zhè ge这个xīng qī星期, xià gè xīng qī下个星期. 星期 takes the measure word 个, which you also need when counting weeks: 一个星期. In "last week" and "next week" 个 is often dropped: 上星期, 下星期.

周 and 礼拜

Zhōu yī周一 to Zhōu liù周六 and Zhōu rì周日 mean the same and are shorter, the usual form in writing and in schedules. lǐ bài礼拜 is a colloquial alternative, more common in the south: 礼拜天.