Insee Focus · September 2025 · n° 360

What day is the peak of birth in France?

Over the last ten years, from 2015 to 2024, the day with the highest average number of births was on the 20th of July, while Christmas Day recorded the fewest. Apart from July, a noticeable concentration of births occurred in late September, reflecting conceptions that took place during the end of year holidays. Births tended to be less frequent on weekends and public holidays.

Since the 1970s, France’s “baby season” shifted from spring to summer. From 1975 to 2010, heat waves were most often followed by a dip in births 9 months later, in April or May. This effect became less pronounced in recent years, as heatwaves grew in frequency. Another striking change was the sharp decline, since the 1970s, of the traditional April baby boom among primary school teachers.