Week 40, 2027
October 4–10, 2027
Monday October 4 – Sunday October 102027-W40Days 277–283
The seven days
| Date | ISO week date | Day of year | US week | Islamic date (computed) | Holidays and other dates |
|---|---|---|---|---|---|
| Mon, Oct 4 | 2027-W40-1 | 277 | 41 | 4 Jumada al-Ula 1449 AH | Labour Day (Australia: New South Wales); King's Birthday (Australia: Queensland) |
| Tue, Oct 5 | 2027-W40-2 | 278 | 41 | 5 Jumada al-Ula 1449 AH | |
| Wed, Oct 6 | 2027-W40-3 | 279 | 41 | 6 Jumada al-Ula 1449 AH | |
| Thu, Oct 7 | 2027-W40-4 | 280 | 41 | 7 Jumada al-Ula 1449 AH | |
| Fri, Oct 8 | 2027-W40-5 | 281 | 41 | 8 Jumada al-Ula 1449 AH | Chung Yeung Festival (Hong Kong) |
| Sat, Oct 9 | 2027-W40-6 | 282 | 41 | 9 Jumada al-Ula 1449 AH | |
| Sun, Oct 10 | 2027-W40-7 | 283 | 42 | 10 Jumada al-Ula 1449 AH |
About week 40
In US numbering, where weeks start on Sunday and the week of January 1 is week 1, Monday to Saturday are US week 41 and Sunday US week 42.
Holidays this week: Labour Day on Mon, Oct 4 in Australia: New South Wales; King's Birthday on Mon, Oct 4 in Australia: Queensland; Chung Yeung Festival on Fri, Oct 8 in Hong Kong. All weeks of 2027 lists the neighbouring weeks.
Week 40 in other years
| Year | Week 40 runs |
|---|---|
| 2025 | Mon, Sep 29 – Sun, Oct 5 |
| 2026 | Mon, Sep 28 – Sun, Oct 4 |
| 2027 | Mon, Oct 4 – Sun, Oct 10 |
| 2028 | Mon, Oct 2 – Sun, Oct 8 |
| 2029 | Mon, Oct 1 – Sun, Oct 7 |
| 2030 | Mon, Sep 30 – Sun, Oct 6 |
In 2028, week 40 runs Mon, Oct 2 – Sun, Oct 8: 364 days later, 2 days earlier in the calendar. Over the 400-year cycle, the Monday of week 40 falls between September 27 and October 4.
By the end of week 40, 283 days of 2027 have passed (77.5% of the year), and 12 ISO weeks of 2027 remain. The week falls in Q4.
Writing week 40
ISO 8601 writes this week as 2027-W40 (basic format 2027W40), from 2027-W40-1 on Monday to -7 on Sunday. The week number page shows the spreadsheet and Python formulas that give these numbers.