birthday traffic

How common are December birthdays?

Published by Birthday Traffic · · Sources and method

December is the 7th most common birth month of the 12, at 10,991 recorded births per day, 1.6% below an average day across 85,712,738 U.S. births from 1994–2014. Its most common date is December 20 (#11 of 366) and its quietest date that occurs every year is December 25 (#365).

Every date is coloured by the same six rarity tiers the reveal uses; the small number is its rank of 366 from most common.

Every December date: recorded U.S. births 1994–2014

One column per December date in calendar order, coloured by rarity tier, total recorded births 1994–2014.

Every December date: recorded U.S. births 1994–2014One column per December date in calendar order, coloured by rarity tier, total recorded births 1994–2014.0100,000200,000300,0001: 237,16012: 235,9903: 235,0774: 231,7935: 234,98656: 231,0847: 226,4398: 229,5729: 228,743910: 231,08711: 229,81712: 241,61513: 228,9591314: 230,85915: 235,88216: 239,30117: 242,3251718: 246,45419: 251,94820: 253,354253,35421: 246,2612122: 240,07823: 218,05124: 170,16625: 138,628138,6282526: 201,57727: 246,21428: 249,92129: 252,0822930: 250,57731: 219,101
Calendar order; each column is the date’s total across the window, in its rarity colour.

Every December date, ranked

Ranked by total recorded births across the 21 years, the same measure as the site-wide rank of 366.

Recorded U.S. births per December date, 1994–2014
DateTotal birthsRank of 366Odds
December 20253,354#111 in 338
December 29252,082#161 in 340
December 19251,948#171 in 340
December 30250,577#231 in 342
December 28249,921#281 in 343
December 18246,454#521 in 348
December 21246,261#541 in 348
December 27246,214#561 in 348
December 17242,325#931 in 354
December 12241,615#991 in 355
December 22240,078#1071 in 357
December 16239,301#1111 in 358
December 1237,160#1371 in 361
December 2235,990#1481 in 363
December 15235,882#1501 in 363
December 3235,077#1661 in 365
December 5234,986#1671 in 365
December 4231,793#2241 in 370
December 10231,087#2331 in 371
December 6231,084#2341 in 371
December 14230,859#2401 in 371
December 11229,817#2641 in 373
December 8229,572#2741 in 373
December 13228,959#2861 in 374
December 9228,743#2901 in 375
December 7226,439#3201 in 379
December 31219,101#3481 in 391
December 23218,051#3511 in 393
December 26201,577#3601 in 425
December 24170,166#3631 in 504
December 25138,628#3651 in 618

December in the year

December has 8.35% of all recorded births in this sample, over 651 observed days. Months are ranked by births per day. On that measure December is #7 of 12, against September at the top (11,811 per day) and January at the bottom (10,721). Full month ranking.

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Sources, method and limits

Main ranking: 85,712,738 recorded U.S. births on 7,670 calendar dates, 1994–2014. CDC/NCHS daily counts for 1994–1999 and Social Security Administration daily counts for 2000–2014, as compiled by FiveThirtyEight and attributed under CC BY 4.0. The overlapping years 2000–2003 are counted once.

Ranks compare totals across the 366 observed month-and-day dates. February 29 occurred 5 times in this window; every other date occurred 21 times, so per-occurrence figures are used wherever seasonality is compared.

Every figure above comes from the administrative records named here, at the granularity those records publish: a day, a month or a year. Coverage and definitions differ between countries and eras, so two sources are combined only where their documentation states the windows are separate, and the page where that happens says so.

Full method, leap-day treatment and definitions.

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