Thinking about them will help you to plan a little better and make sure that all involved have a good time. With proper care, any time of the year can be enjoyed, but there are a few times that are better than others. One of the best times is in December up to the week before Christmas. The crowds are light, the weather cool, and the parks are decorated for the holidays. Another good time is in January after the first week until mid-February.
Summers tend to be too crowded and extremely hot.
It is very taxing on anyone, but especially so on a small child. Holiday periods are very crowded and make pushing a stroller very difficult. Long attraction lines lead to restlessness and limit the amount of attractions that can be experienced. Spring Break is very crowded and warm. Early October thru early November sports great weather and low crowds.