Yes, compared with most dates. May 26 is among the less common birthdays in these historical U.S. records. It ranks #349 of 366 dates by total births from 1994 through 2014. Rank #1 means most common.
May 26 had 218,924 births across 21 occurrences, or 10,425 births per occurrence. That is 0.255% of the 85,712,738-birth sample, or about 1 in 392 recorded births.
It has the fewest births of the 31 May dates.
What happens when May 26 is Memorial Day?
In SSA 2000–2014, May 26 was Memorial Day three times, in 2003, 2008, and 2014. In those years, it had 35.4% fewer births than nearby same-weekday dates.
In the other 12 years, May 26 had 0.5% more births than its controls. The lower full-period result comes from the holiday years, not from every May 26.
The May guide uses the 1994–2014 baseline. That period adds a fourth Memorial Day year, 1997, so its figures differ from these SSA results.
Across all 15 years, the primary comparison gives -7.3%. With only the 7-day or only the 14-day controls, the results are -7.9% and -6.7%.
Baseline ranks use historical U.S. CDC/NCHS and SSA records, 1994–2014. The percentage differences use SSA 2000–2014 alone. Each table row compares May 26 with controls from the same year.
| Comparison | Years | Control observations | Difference |
|---|---|---|---|
| 7 and 14 days, holidays excluded (primary) | 15 | 60 | -7.3% |
| 7 days only | 15 | 30 | -7.9% |
| 14 days only | 15 | 30 | -6.7% |
| 7 and 14 days, no holiday exclusions | 15 | 60 | -7.3% |
| Memorial Day years only | 3 | 12 | -35.4% |
| Other years only | 12 | 48 | +0.5% |
How were the comparison dates chosen?
The primary controls are May 12, May 19, June 2, and June 9 in the same year. Each is 7 or 14 days from May 26, so it falls on the same weekday.
None of these controls fell on an excluded holiday. We exclude holidays under the standard observed federal holiday rules. We also exclude Christmas Eve, December 26, and the Friday after Thanksgiving.
By five-year period, the primary differences are -7.5% for 2000–2004, -6.9% for 2005–2009, and -7.8% for 2010–2014.
To combine the years, we divide the summed target births by the summed annual control means. Then we subtract one and multiply by 100. The result is not an average of annual percentages.
Does the May 26 rank change over time?
Somewhat, but less than most dates. We ranked 365 recurring dates by SSA births in each five-year period. May 26 placed #360 in 2000–2004, #251 in 2005–2009, and #357 in 2010–2014. The three ranks span 109 places.
The median span for all 365 recurring dates is 159 places. This span is below that median.
Each period has only five occurrences of May 26. It fell on a weekend twice in 2000–2004, twice in 2010–2014, and once in 2005–2009. The periods with more weekend occurrences have less common ranks.
Each period contains one Memorial Day year, so holiday years do not explain the movement.
These ranks use raw birth counts. The ranking-stability study also compares annual shares and weekday-relative scores for every date.
Sources and limits
Baseline totals and ranks use FiveThirtyEight’s pinned U.S. birth files. We use CDC/NCHS for 1994–1999 and SSA for 2000–2014, so no year comes from both sources. Annual comparisons use SSA alone.
The source series have different administrative coverage. These records do not describe worldwide births, everyone alive today, or current birth rates.
The daily totals do not record delivery methods or scheduling decisions. Weekday matching does not remove every seasonal difference. Federal holiday rules identify calendar dates, not hospital schedules.
Use the May guide for the full month ranking. See also the May 5 study.
The Memorial Day birth study follows every actual Memorial Day.
The methodology explains ranks and shares. Use the birthday checker to compare another date.