December 31 is an uncommon birthday in these historical U.S. records, but it is more common than Christmas Day or New Year's Day. It ranks #348 among all 366 birthday dates, with 219,101 births from 1994 through 2014. Rank #1 means most common.
New Year's Eve accounts for 0.256% of births in the dataset, or about 1 in 391. That describes recorded births during this period, not the odds for every population or the number of people alive with the date.
December 31, beside other birthdays
Average recorded births each time a date occurred, 1994 through 2014.
- Commonness rank
- 348 / 366
- Share of recorded births
- 0.256 %
- Recorded births
- 219,101
Bars start at zero. Rank 1 means most common and uses total births across all 366 dates. The bars use births per actual occurrence; February 29 appeared five times, while the other dates appeared 21 times.
Check December 31 and compare with a friend →How does New Year's Eve compare with nearby birthdays?
December 30 has a much higher total than December 31. January 1 has a lower one. December 25 is lower still. The year boundary sits between dates with quite different frequencies, so treating New Year's Eve and New Year's Day as interchangeable would hide the pattern.
| Date | Recorded births | Commonness rank | Birth share |
|---|---|---|---|
| December 24 | 170,166 | 363 | 0.199% |
| December 25 | 138,628 | 365 | 0.162% |
| December 30 | 250,577 | 23 | 0.292% |
| December 31 | 219,101 | 348 | 0.256% |
| January 1 | 164,362 | 364 | 0.192% |
| January 2 | 196,481 | 361 | 0.229% |
Every date in this table occurred 21 times. December 31 averages 10,433.4 births per actual occurrence. Unlike leap day, December 31 has the same number of calendar appearances as these other dates.
For the surrounding month, use the December birthday guide. The separate New Year's Day explanation and Christmas birthday explanation show why these low-frequency dates should be read individually.
Why does the nearby-weekday result need care?
A raw December 30 and 31 comparison involves different weekdays. To compare the same weekday across nearby weeks, we use SSA records from 2000 through 2014 and compare December 31 with December 17 and December 24 in each year.
These dates are two weeks and one week before December 31. We keep comparisons inside the same calendar year, so January 7 and January 14 of the next year are excluded. This also means Christmas Eve is half of the comparison average.
The pooled result puts December 31 6.6% above that average. It is above the comparison in 13 of 15 years. Christmas Eve helps pull that average down. The positive result therefore does not establish that New Year's Eve is above ordinary nearby dates.
| Year | Weekday | Recorded births | Nearby mean | Difference |
|---|---|---|---|---|
| 2000 | Sunday | 7,892 | 7,498.5 | +5.2% |
| 2001 | Monday | 10,272 | 10,009 | +2.6% |
| 2002 | Tuesday | 12,582 | 11,292.5 | +11.4% |
| 2003 | Wednesday | 12,540 | 11,363 | +10.4% |
| 2004 | Friday | 10,130 | 10,451.5 | -3.1% |
| 2005 | Saturday | 8,635 | 7,978.5 | +8.2% |
| 2006 | Sunday | 7,569 | 7,224.5 | +4.8% |
| 2007 | Monday | 11,102 | 10,591 | +4.8% |
| 2008 | Wednesday | 12,906 | 11,524.5 | +12.0% |
| 2009 | Thursday | 11,667 | 10,933 | +6.7% |
| 2010 | Friday | 9,751 | 10,180.5 | -4.2% |
| 2011 | Saturday | 8,035 | 7,314.5 | +9.9% |
| 2012 | Monday | 10,634 | 9,796.5 | +8.5% |
| 2013 | Tuesday | 12,525 | 11,223 | +11.6% |
| 2014 | Wednesday | 11,990 | 10,996 | +9.0% |
The two comparison weeks tell different stories. Against December 24 alone, the signed difference is +31.3%; against December 17 alone, it is -10.2%. The sign reverses. December 31 falls between the two comparison dates in the pooled counts, rather than showing one direction against both.
Do these records explain why births are lower?
They show when births were recorded. They do not include delivery methods, intended delivery dates or family decisions. We cannot attribute the December 31 ranking to holiday scheduling from these counts alone. The holiday birth study examines other holiday comparisons and explains the same limit.
The annual table shows counts varying as December 31 falls on different weekdays. It does not isolate how much of that variation comes from the weekday. Matching weekdays makes the comparison closer, but other differences between dates remain.
Sources and ranking rules
The established rank and odds use U.S. daily birth files compiled by FiveThirtyEight: CDC/NCHS 1994 through 1999 plus SSA 2000 through 2014, with overlapping CDC years excluded. The annual comparisons use SSA alone. Different source systems have different administrative coverage.
The methodology explains how counts, shares and ranks are calculated. These are historical U.S. results, not a worldwide ranking or current-year forecast. Browse the full rare-birthday ranking or use the birthday checker to compare December 31 with another date.
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