The rarest birthday in United Kingdom
February 29 is a special case because it exists only in leap years. The recurring-date result gives a fairer comparison among birthdays that appear on the calendar every year.
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The 10 rarest birthdays in the United Kingdom model
The list is ordered from the lowest modeled daily percentage upward. A rank of #1 is the rarest position.
February 29
0.066% of birthdays in the model, about 0.66 per 1,000. That is 75.7% below the average calendar date.
Leap Day appears only in leap years and has the lowest value in the current model.
Check February 29 in the calculatorJanuary 1
0.085% of birthdays in the model, about 0.85 per 1,000. That is 68.8% below the average calendar date.
New Year's Day receives one of the model's strongest fixed-date holiday adjustments.
Check January 1 in the calculatorDecember 25
0.085% of birthdays in the model, about 0.85 per 1,000. That is 68.8% below the average calendar date.
Christmas Day receives one of the model's strongest fixed-date holiday adjustments.
Check December 25 in the calculatorApril 1
0.142% of birthdays in the model, about 1.42 per 1,000. That is 48.0% below the average calendar date.
April 1 is one of the fixed special dates assigned a lower value in the current model.
Check April 1 in the calculatorDecember 24
0.142% of birthdays in the model, about 1.42 per 1,000. That is 48.0% below the average calendar date.
Christmas Eve sits inside the quieter year-end holiday period represented in the model.
Check December 24 in the calculatorDecember 31
0.142% of birthdays in the model, about 1.42 per 1,000. That is 48.0% below the average calendar date.
New Year's Eve is treated as a quieter special date in the current model.
Check December 31 in the calculatorOctober 31
0.171% of birthdays in the model, about 1.71 per 1,000. That is 37.6% below the average calendar date.
This date falls well below the average daily value in the selected country model.
Check October 31 in the calculatorDecember 26
0.171% of birthdays in the model, about 1.71 per 1,000. That is 37.6% below the average calendar date.
This date remains inside the quieter year-end holiday period represented in the model.
Check December 26 in the calculatorJanuary 2
0.237% of birthdays in the model, about 2.37 per 1,000. That is 13.2% below the average calendar date.
This date falls well below the average daily value in the selected country model.
Check January 2 in the calculatorDecember 30
0.237% of birthdays in the model, about 2.37 per 1,000. That is 13.2% below the average calendar date.
This date falls well below the average daily value in the selected country model.
Check December 30 in the calculatorHow the rarest dates compare across six countries
The current models agree on the broad pattern, while small country-specific differences can change the percentages and the order of nearby dates.
| Country | Rarest date | Rarest recurring date | Quietest month |
|---|---|---|---|
| United States | February 29 (0.067%) | January 1 | December |
| Canada | February 29 (0.067%) | January 1 | December |
| United Kingdom | February 29 (0.066%) | January 1 | December |
| Australia | February 29 (0.066%) | January 1 | December |
| New Zealand | February 29 (0.066%) | January 1 | December |
| Ireland | February 29 (0.066%) | January 1 | December |
Why Leap Day and holiday dates rank near the rare end
Leap Day: February 29 exists only in leap years, so it is inherently different from annually recurring dates. The current model also gives it the lowest daily percentage.
Holiday dates: The model includes lower fixed-date values for selected major holidays and the quieter year-end period. That is why New Year and Christmas dates often appear near the rare end.
These notes explain the construction of the current model. They should not be interpreted as proof that every country has identical observed birth patterns.
How to interpret a rare birthday
A rare rank is relative. It means the date has a lower modeled frequency than most other dates, not that only a handful of people share it. Even the rarest birthdays are shared by many people.
For the opposite end of the same table, August 31 ranks as the most common birthday in the United Kingdom model. The birthday statistics page places both ends beside the monthly pattern.
Rarest birthday questions
What is the rarest birthday?
In the current United Kingdom model, February 29 ranks first.
What is the rarest birthday that happens every year?
Excluding February 29, the lowest-frequency date is January 1.
Are the rarest birthdays identical in every country?
The current models share the same broad pattern, but daily percentages and the order of nearby dates can differ.
Does a rare birthday make someone more unique?
No. The ranking describes a calendar date, not a person's individuality or personality.