I blog anytime of the day i have free time...most often when my baby is napping or in bed. Blogger has a post date feature I love so that I can continue you save it while i'm working on a post and have it scheduled for any time.
I love that about WordPress too. I find that I don't have a set time either...we all know that, unfortunately, motherhood isn't very predictable from day to day! But I find I do a lot of blogging at night and then schedule a post for the early morning.