scorecardresearch

What’s the most popular birthday in Massachusetts?

Andre DeCorzo Jr. concentrated on his “smash cake” during his birthday party at the Children’s Museum of Fall River in October.
Andre DeCorzo Jr. concentrated on his “smash cake” during his birthday party at the Children’s Museum of Fall River in October.(Pat Greenhouse/globe staff/file 2015)

If today’s your birthday — congrats! And, you’re not alone.

June 27 is the most popular birthday in Massachusetts, according to data from the state’s Department of Public Health.

Between 2005 and 2014, an average of 232.2 people were born on June 27 each year, the figures show.

The data detailed the birthdays of more than 750,000 people over that 10-year span.

The next most popular date of birth was Sept. 19, and it was a close second, with an annual average of 231.8 people born on that date during those years.

February 29, or Leap Day, was – by far – the least popular. For obvious reasons. It only came around twice during the 10-year period.

Advertisement



An annual average of just 37.9 people were born on that date, some in 2008 and the rest in 2012.

The next most uncommon date was a birthday that billions of people around the world celebrate.

A yearly average of only 130.8 people were born on Dec. 25, which Christians honor annually as the birth of Jesus.

The next least common birthday was Jan. 1, or New Year’s Day, with 140.8 people per year, on average.

Other uncommon birthdays also seem to fall around holidays, including Christmas, Thanksgiving, New Year’s Day, and the Fourth of July.

The data also shows that weekend births were significantly less common than weekday ones. The most common day to be born was a Friday, which averaged 230.1 births per day; the least common was a Sunday, which averaged 148.2 births per day.

Micaela Martinez-Bakker, a postdoctoral fellow at Princeton University, said the most likely reason why births occur much less often on weekends and holidays is because, in modern society, many deliveries are scheduled, either via induced labor or cesarean section procedures.

Martinez-Bakker co-authored a study showing how births tend to surge during certain seasons. She found that when those peaks occur varies based on how far people live from the equator.

Advertisement



The research, which focused on data from the US and other countries in the Northern Hemisphere, found that areas farther north of the equator tend to see births peak in early to mid-summer, while southern areas see their annual jump in births in late summer or autumn. Southern areas also see a more dramatic spike each year.

But researchers have not yet figured out what exactly causes seasonal variations in birth rates, Martinez-Bakker said.

“It’s still an open question,” she said. “There are probably multiple factors causing it, but we’ll also probably never know exactly what’s causing it.”

She said the causes stem either from seasonal changes to humans’ bodies that make it easier to conceive a child or changes in people’s behavior that increase the odds for pregnancy — or a combination of the two.

The phenomenon is important to study and it has real consequences, she said. If areas see particularly large increases in the number of babies being born at certain times, it can increase the odds for outbreaks of illnesses, particularly of childhood diseases.

(To see a full list of birthday dates and their popularity, click here.)

The three charts below show the most popular months (between Jan. and Dec.), the most popular days of the week (Sunday through Saturday), and the most popular day numbers within a month (between 1 and 31).

Advertisement



Most common birth months
This chart shows most popular birth months based on state public health data about more than 750,000 people born in Massachusetts between 2005 and 2014. Months are ranked using adjustments made to account for the varying number of days in each month.
Month Rank Average births per year Days per month Average births per day
August 1 6,728 31 217.0
July 2 6,670 31 215.2
June 3 6,443 30 214.8
September 4 6,407 30 213.6
May 5 6,521 31 210.3
April 6 6,166 30 205.5
October 7 6,354 31 205.0
March 8 6,271 31 202.3
February 9 5,597 28.2* 198.5
November 10 5,892 30 196.4
December 11 6,028 31 194.4
January 12 5,993 31 193.3

*February figure is adjusted to account for two Leap Years between 2005 and 2014.

SOURCE: Massachusetts Department of Public Health
Most common day of the week to be born
This chart shows most popular day of the week to be born based on state public health data about more than 750,000 people born in Massachusetts between 2005 and 2014. Days are ranked using adjustments made to account for the varying number of times each day occurred over that 10-year span.
Day of week Rank Births Times weekday occurred, 2005-2014 Average births per day
Friday 1 119,907 521 230.1
Thursday 2 119,491 521 229.3
Tuesday 3 119,321 522 228.6
Wednesday 4 117,937 522 225.9
Monday 5 109,018 522 208.8
Saturday 6 87,660 522 167.9
Sunday 7 77,369 522 148.2
SOURCE: Massachusetts Department of Public Health
Most common day number to be born
This chart shows most popular day numbers to be born based on state public health data about more than 750,000 people born in Massachusetts between 2005 and 2014. Day numbers are ranked using adjustments made to account for the varying number of days in each year.
Day number Rank Average births per year Times date occurs annually Average births per day
15 1 2,508 12 209.0
7 2 2,503 12 208.6
19 3 2,502 12 208.5
14 4 2,500 12 208.3
21 5 2,499 12 208.2
18 6 2,497 12 208.0
3 7 2,491 12 207.6
8 8 2,490 12 207.5
9 9 2,490 12 207.5
17 10 2,489 12 207.4
22 11 2,483 12 206.9
29 12 2,317 11.2* 206.9
10 13 2,482 12 206.8
6 14 2,474 12 206.2
11 15 2,472 12 206.0
28 16 2,470 12 205.9
12 17 2,469 12 205.8
16 18 2,467 12 205.6
2 19 2,458 12 204.9
30 20 2,252 11 204.7
1 21 2,456 12 204.7
27 22 2,454 12 204.5
20 23 2,452 12 204.4
23 24 2,452 12 204.4
5 25 2,447 12 203.9
31 26 1,423 7 203.2
24 27 2,437 12 203.1
4 28 2,429 12 202.4
26 29 2,409 12 200.8
25 30 2,408 12 200.6
13 31 2,391 12 199.3

*This figure for day number 29 is adjusted to account for two Leap Years between 2005 and 2014.

SOURCE: Massachusetts Department of Public Health

(To see a full list of birthday dates and their popularity, click here.)


Matt Rocheleau can be reached at matthew.rocheleau@globe.com. Follow him on Twitter @mrochele