I have a June and a March baby. If we went for a similar age gap again, I'd have a Nov/Dec baby. I therefore want to wait slightly longer next time (if we have a third) so that the baby would be due in spring again. Ideally, the earliest I'd want would be February as I just don't think I'd enjoy the newborn stage when the days are so cold and short. Spring is just lovely for getting out with the pram.
As I found with my first though, it doesn't necessarily happen when you plan, and I wouldn't stop trying if I was coming towards a less favourable time of year.