I once read that there are the fewest births in March because more babies are conceived in winter when we're indoors more, and born in summer/fall. March babies would have to have been conceived in the middle of hot summer!

Charlie was born in December so he was conceived in March, and Olive was conceived in February and born in October (though she was supposed to be born in November).

So Mr. Bee was born in September, Olive and I were born in October, and Charlie was born in December!