March was the peak month in every year from 1955 to 1976. September led after that run in 1977, though later years had exceptions.
Official birth records · A calendar of changing seasons
When are babies born?
The answer has changed over time. March led through the 1960s and early 1970s. September now has the strongest run of birthdays, while weekdays and holidays leave their own mark.
1938–2025England & Wales · monthly
1995–2025England & Wales · daily
25 & 26 SepNear-tied historical leaders
Four nationsCompare monthly patterns below
These are past birth counts. They cannot tell us which date will be busiest this year.
01 / YOUR DATE · ENGLAND & WALES
How common is a birthday?
Choose a day and month. The result is its average share of England and Wales births in each year, from 1995 to 2025.
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“1 in N” is a historical share of all births, not the probability for a particular pregnancy. A single year's busiest day can be quite different.
Across the calendar year
Mean share of annual births on each fixed date
Leap-day births remain in each leap year's denominator. 29 February is shown separately because it occurred in only eight of the 31 years.
See the nearby dates as a table
| Date | Mean share | About 1 in | Rank |
|---|
02 / 88 YEARS · ENGLAND & WALES
Travel through the months
Births per day make February and March comparable with longer months. Index 100 means that year's average daily number of births.
Try:
Teal tiles are above that year's mean daily birth rate; coral tiles are below it. The outlined tile is the year's highest month by births per day.
See all twelve months as a table
| Month | Births | Births per day | Index |
|---|
03 / FOUR NATIONS · MONTH BY MONTH
Does the season change
across the UK?
Compare the same complete years in England, Wales, Scotland and Northern Ireland. Index 100 is each nation's own annual daily average.
Try:
Loading the four-nation monthly record…
England, Wales and Northern Ireland are grouped by mothers' residence; Scotland is grouped by where the birth occurred. The comparison describes seasonal timing. A mother's residence can differ from the maternity unit's location.
The shape of a birth year
Average monthly births per day, relative to each year's daily mean.
Each year has equal weight. A value of 105 means births per day were 5% above that year's daily average. Month length, including leap years, is accounted for.
How pronounced is the monthly pattern?
Highest minus lowest monthly index in each year · percentage points
A bigger spread means a more uneven year. It includes calendar effects, fluctuations and within-year changes in birth numbers as well as recurring seasonality; it does not identify their causes.
Compare the twelve months as a table
Coverage, definitions and original sources
Separate England/Wales residence months are available for January 1982–August 2008 and September 2009–August 2025. September 2008–August 2009 remains unsourced here. 2025 is partial and provisional for the residence split. Only complete years enter these charts.
Different ONS extracts do not always reconcile exactly. Country indices use the sum of their own twelve published source months. In 2010–2024, the largest national monthly difference from the combined daily series is 1.57%; country annual sums differ from the 2025 annual controls by at most 0.20%. Counts have not been rescaled. Download the monthly reconciliation or annual country checks.
Download all available monthly series with provenance. ONS, NRS and NISRA data are reproduced under the Open Government Licence.
04 / DAY BY DAY · ENGLAND & WALES
See the rhythm of a year
Pick a year to see England and Wales daily counts. The regular dips are mainly weekends; Christmas and Boxing Day stand out too.
05 / WHAT THE NUMBERS SAY · ENGLAND & WALES
What held up to scrutiny?
The figures below are direct calculations from ONS counts. They describe birth timing, not the cause of a conception.
Each accounts for about one in 339 births in the 1995–2025 daily record. Their difference is tiny. Neither is a forecast winner.
Weekend daily births average about 17% below weekdays. Christmas Day is about 24% below the mean for its weekday in that year.
A September birth window corresponding to a 266-day shift from Christmas–New Year was above its weekday baseline across three modern periods: 106.2, 106.8 and 106.3. These data do not show steady fading.
The long-run monthly pattern was weaker in 1995–2025 than in 1955–76, measured by the mean annual peak-to-trough range. A continuing decline since 1995 was not established. Birth records alone cannot tell us when a particular child was conceived, and planned delivery affects exact dates.
06 / SOURCES
Method and data
Built from published aggregate ONS, NRS and NISRA tables. Plausible records aggregate visits, outbound link clicks and downloads. This site has no accounts or personal calendar records.
Monthly, 1938–2025
Exact monthly births by occurrence. Each month's count is divided by the actual number of calendar days, then compared with that year's mean daily births. The 1992–94 bridge comes from a separate overlapping ONS occurrence table.
Download monthly CSVDaily, 1995–2025
ONS Table 12 daily births by occurrence, including the small number to mothers usually resident elsewhere. Date shares are calculated within each year before taking the 31-year average. Weekday and holiday comparisons are likewise calculated within each year.
Download daily CSVOriginal ONS tables: 1938–91 · 1992–94 bridge · 1995–2025 daily, 2025 edition. ONS information is reproduced under the Open Government Licence.
The birthday lookup ranks dates by mean share of each year's births. ONS's 2025 bulletin ranks dates by mean birth count: for 28 May, that gives rank 168 there and rank 170 here. This explorer is an independent analysis, not an ONS publication. Historic observations can be revised in later ONS editions. It makes no prediction about any future year's busiest day.