A few weeks ago I have posted about the birthday paradox, but what the math there does not consider is that birthdays are not equally distributed across the year. As one can imagine that are days or months when more babies are born than on other dates. Matt Stiles has made some birthday statistics and generated this nice looking heat-map.
It seems that more babies are born in the summer months, but there is hardly any noticeable pattern across each month. However, the results need to be used with caution as they are only representative for the US. It would be good to have such heat maps for other countries, respectively for the whole population. Moreover, it would be interesting to see if in the Southern hemisphere more babies are born between December and February as this marks the peak of the summer season there?