Day 31 of the year
The 31st day of 2026 is Saturday, January 31, 2026. It was 235 days ago.
Where day 31 lands in other years
The calendar date for a given day number moves only because of leap years. In a common year day 31 is one date; from 1 March in a leap year it shifts back by one.
| Year | Date | Weekday | Leap year |
|---|---|---|---|
| 2026 | January 31 | Saturday | no |
| 2027 | January 31 | Sunday | no |
| 2028 | January 31 | Monday | yes |
| 2029 | January 31 | Wednesday | no |
| 2030 | January 31 | Thursday | no |
Day 31 in context
Day 31 sits in January, on the 31st of the month, in the first quarter. By that point 30 days of the year have already gone and the year is 8.5% complete.
| Anchor | Day number | Distance from day 31 |
|---|---|---|
| 1 January | 1 | 30 days before |
| 1 April | 91 | 60 days after |
| 1 July | 182 | 151 days after |
| 1 October | 274 | 243 days after |
| 31 December | 365 | 334 days after |
Counting to and from day 31
Ordinal day numbers make in-year arithmetic trivial: the gap between two dates in the same year is just the difference of their day numbers. Day 31 minus today's day 266 gives 235 days, with no month lengths to reason about. That is exactly why batch codes, expiry stamps and flight schedules use them.
Questions
- What date is day 31 of the year?
- Saturday, January 31, 2026.
- What weekday is it?
- A Saturday in 2026.
- How far away is it?
- 235 days ago.
Reading the number back
To go the other way, from a calendar date to a day number, add up the lengths of the months before it and then add the day of the month. For January 31 in 2026 that is 0 days across the earlier months plus 31, giving 31. The only wrinkle is February, which is why the same date can carry two different day numbers depending on whether the year is a leap year.