I am taking my boys (age 4, 7, 9) to DLR tomorrow. We will be in the parks from about 9am-9pm. Does it ever get chilly enough that we will need sweatshirts? We've been many times before, but never in the summer
DH and I were there last Friday and I was in a tank top & shorts until we left at midnight...however; it was really hot and humid last week. The temps have cooled dramatically this week and I'd say you will need a sweatshirt once the sun goes down.
Its forcasted to be in the low 70s early and late in the day and in the low 80s during the afternoon. If that is the type of weather that you need sweat shirts for then bring them.
At Disneyland, for some reason, when the sun goes down I often get cold. Especially if it's been very hot that day; when the temperature comes down it makes it worse for me. I've said it before...I'm not sure I'm totally a warm blooded mammal, since i have problems regulating my body temperatures!
You might considering bringing them or bringing extra souvenir money, because buying a new sweatshirt can be a fun thing to do.