December 31
Let an agent handle December 31 as a calendar date with weekday computation, observances attributed to their traditions and sourced events.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify
Researched by: Claude
Purpose and description
Let an agent handle December 31 as a calendar date with weekday computation, observances attributed to their traditions and sourced events.
December 31, day 365 (day 366 in leap years) of the year in the Gregorian calendar, with 0 days remaining; it is the last day of the year in both common and leap years. Observances on this date vary by country and tradition; it is New Year Eve in the Gregorian calendar.
What it is for: A calendar date for scheduling, holidays and anniversaries.
It can be compute its weekday in a given year; check local and international observances; find sourced historical events; schedule events.
Distinguishing features
The thirty-first day of December
Weekday varies by year
Observances vary by place
Julian and Gregorian dates differ by 13 days in this era
What it looks like
A date on calendars.
Physical character
day of year: 365 or 366 day - common year, leap year where different
days remaining: 0 days
How it is recognised
Written 31 December or December 31
ISO format --12-31
Observances vary by country and tradition
Related models
is part of - month
follows - date
is a kind of - category
is expressed in - notation
In practice
Families and kinds
the recurring calendar date
specific dated days in given years
Identifiers
ISO 8601 --12-31 recurring date
Standards and regulation
ISO 8601
National public holiday laws
Failure modes and hazards
Assuming observances are universal
Unsourced on-this-day events
Mixing Julian and Gregorian dates
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 4 bundles · 8 layers · 8 findings · 16 questions.
Date Calendar facts.
Calendar arithmetic.
Weekday
Computation.
Weekday
Weekday.
- On which weekday does December 31 fall in this year? measurement
- Is it a leap year? boundary
Calendar
Julian or Gregorian.
Calendar
Calendar system.
- Is the Julian or Gregorian calendar meant? boundary
- What is the equivalent date in the other calendar? measurement
Observances Holidays.
Observances vary.
Holiday
Public holiday.
Holiday
Holiday status.
- Is December 31 a public holiday or observance here? provenance
- Which tradition or law sets it? provenance
Attribution
Traditions.
Attribution
Attributed observances.
- Which countries or communities observe something on this date, according to them? provenance
- Is the observance attributed rather than assumed? boundary
History Past events.
Events need sources.
Events
On this day.
Events
Historical events.
- Which notable events happened on December 31, according to reliable sources? provenance
- Are dates given in the same calendar? boundary
Anniversaries
Recurring.
Anniversaries
Anniversaries.
- Which anniversaries fall on this date this year? provenance
- Which are round numbers? measurement
Planning Scheduling.
Dates drive plans.
Countdown
Days until.
Countdown
Countdown.
- How many days until the next December 31? measurement
- From which date? definition
Work
Working day.
Work
Working day.
- Is it a working day for this organisation? provenance
- Do deadlines move? boundary
What the second pass must settle
- Should dated days be separate entries?
- How should observances be linked?
- How should events be sourced?