Week numbers for 2027
2027 has 52 ISO weeks. Weeks start on Monday; week 1 contains the first Thursday of the year, following ISO 8601.
- 1 4–10 January
- 2 11–17 January
- 3 18–24 January
- 4 25–31 January
- 5 1–7 February
- 6 8–14 February
- 7 15–21 February
- 8 22–28 February
- 9 1–7 March
- 10 8–14 March
- 11 15–21 March
- 12 22–28 March
- 13 29 March – 4 April
- 14 5–11 April
- 15 12–18 April
- 16 19–25 April
- 17 26 April – 2 May
- 18 3–9 May
- 19 10–16 May
- 20 17–23 May
- 21 24–30 May
- 22 31 May – 6 June
- 23 7–13 June
- 24 14–20 June
- 25 21–27 June
- 26 28 June – 4 July
- 27 5–11 July
- 28 12–18 July
- 29 19–25 July
- 30 26 July – 1 August
- 31 2–8 August
- 32 9–15 August
- 33 16–22 August
- 34 23–29 August
- 35 30 August – 5 September
- 36 6–12 September
- 37 13–19 September
- 38 20–26 September
- 39 27 September – 3 October
- 40 4–10 October
- 41 11–17 October
- 42 18–24 October
- 43 25–31 October
- 44 1–7 November
- 45 8–14 November
- 46 15–21 November
- 47 22–28 November
- 48 29 November – 5 December
- 49 6–12 December
- 50 13–19 December
- 51 20–26 December
- 52 27 December – 2 January
Dates run from Monday to Sunday. A week spanning two calendar years belongs to the ISO week-year containing its Thursday.