Week 40 of 2025 runs September 29, 2025 to October 5, 2025.
Week 40 starts on Monday, September 29, 2025 and ends on Sunday, October 5, 2025. It's the 272nd day of the year, sits in Q3, and falls in September / October. By the end of this week, 278 of 365 days are gone, putting 2025 at 76.2%.
There are no public holidays this week, so all 5 weekdays are working days. Need a different week? Browse the full 2025 week calendar, or jump to this week's number.
Week 40 at a glance
The 7 days of week 40
Every date in week 40 of 2025, Monday through Sunday, with day-of-year numbers and events.
| Day | Date | Day no. | Type | Events |
|---|---|---|---|---|
| Monday | Day 272 | Weekday | ||
| Tuesday | Day 273 | Weekday | ||
| Wednesday | Day 274 | Weekday | ||
| Thursday | Day 275 | Weekday | ||
| Friday | Day 276 | Weekday | ||
| Saturday | Day 277 | Weekend | ||
| Sunday | Day 278 | Weekend |
What week 40 of 2025 means
ISO 8601 numbers weeks so every week starts on Monday and ends on Sunday. Week 1 is the one holding the year's first Thursday, which is why early January can land in week 52 or 53 of the previous year. Week 40 is one piece of that system.
In 2025, week 40 covers Sep 29 – Oct 5, 2025. That's September / October, deep in Q3. The same week number shifts by a day or two each year, so week 40 in 2026 won't share these exact dates. The table below shows how it moves.
Want to check a specific date instead of a week number? The week calculator converts any date to its ISO week. Curious how many weeks a year holds? The weeks in a year guide explains 52 versus 53. And the ISO week number page covers the standard end to end.
Holidays in week 40 of 2025
🇨🇦 Canada
National Day for Truth and Reconciliation
FederalWeek 40 across years
The same ISO week number lands on different dates each year. Here's how week 40 shifts.
Week 40 of 2025: questions and answers
What days are in week 40 of 2025?
Week 40 of 2025 runs from September 29, 2025 (Monday) through October 5, 2025 (Sunday). It spans September / October.
What month is week 40 in 2025?
Week 40 of 2025 spans two months: it starts in September and ends in October 2025.
How many working days are in week 40 of 2025?
Week 40 of 2025 has 5 working days.
What quarter is week 40 of 2025 in?
Week 40 of 2025 is in Q3 (2025). The week starts on day 272 of 365.
What is ISO week 40?
ISO week 40 is defined by the ISO 8601 international standard. It begins on Monday, September 29, 2025, and ends on Sunday, October 5, 2025. It is week 77% through the ISO year 2025.