Week 21 of 2026 runs May 18, 2026 to May 24, 2026.
Week 21 starts on Monday, May 18, 2026 and ends on Sunday, May 24, 2026. It's the 138th day of the year, sits in Q2, and falls in May. By the end of this week, 144 of 365 days are gone, putting 2026 at 39.5%.
There are no public holidays this week, so all 5 weekdays are working days. Need a different week? Browse the full 2026 week calendar, or jump to this week's number.
Week 21 at a glance
The 7 days of week 21
Every date in week 21 of 2026, Monday through Sunday, with day-of-year numbers and events.
| Day | Date | Day no. | Type | Events |
|---|---|---|---|---|
| Monday | Day 138 | Weekday | ||
| Tuesday | Day 139 | Weekday | ||
| Wednesday | Day 140 | Weekday | ||
| Thursday | Day 141 | Weekday | ||
| Friday | Day 142 | Weekday | ||
| Saturday | Day 143 | Weekend | ||
| Sunday | Day 144 | Weekend |
What week 21 of 2026 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 21 is one piece of that system.
In 2026, week 21 covers May 18 – May 24, 2026. That's May, deep in Q2. The same week number shifts by a day or two each year, so week 21 in 2027 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 21 of 2026
No major public holidays in week 21 of 2026 across the US, UK, Canada, or Australia.
Week 21 across years
The same ISO week number lands on different dates each year. Here's how week 21 shifts.
Week 21 of 2026: questions and answers
What days are in week 21 of 2026?
Week 21 of 2026 runs from May 18, 2026 (Monday) through May 24, 2026 (Sunday). It spans May.
What month is week 21 in 2026?
Week 21 of 2026 falls entirely in May 2026.
How many working days are in week 21 of 2026?
Week 21 of 2026 has 5 working days.
What quarter is week 21 of 2026 in?
Week 21 of 2026 is in Q2 (2026). The week starts on day 138 of 365.
What is ISO week 21?
ISO week 21 is defined by the ISO 8601 international standard. It begins on Monday, May 18, 2026, and ends on Sunday, May 24, 2026. It is week 40% through the ISO year 2026.