Personally I don't think it matters too much if you aren't taking school aged children. A lot of spaces will open up in September so you will have more competition for spots out there. I find that parents tend to leave it until August before they get too serious about looking for September likely because they are busy on holidays. It can be hit or miss. Last year I had a spot in Sept and I didn't fill it until October. I had spots open in Feb and again in May but found most were looking for care to start June/July. It is all over the place sometimes.

If I was you I would just pick a start date that suites you and your family and stick to it.