By the time cold and flu season hit, your little one will be old enough so you aren't as worried about exposure.
You have a little one old enough to bring to family holiday gathering without too much fear of exposure and such, but young enough to be the tiny new exciting baby. At Thanksgiving and Christmas they're still so easily transportable - EBF slinglings, and you're recovered from the birth.
You get to announce your pregnancy at Christmas time. We've done that twice now. It's so fun to announce the pregnancy to the whole family gathered together instead of by phone and such.
If you plan to send your little one to school, at least here, your little one just makes the school cut off date, so you can choose to start them as a young 5 or wait until they're 6 depending on your child's needs and personality. A month later they HAVE to wait and start when they're almost 6 and they're stuck being oldest even if they would have been better off starting earlier.
Gift giving occasions of birthday, Christmas, and perhaps Easter, are well spread out in the year.
You can easily dress your tiny one in just a onsie.
It's beautiful and warm outside for taking tiny newborn pictures.
There are many more. I'm a late July birthday and DD is August. Here I am doing it all over again
I think the summer is the perfect time to have a baby