Hi Bronte,
Florida IS hot in July, like everywhere but Ireland(!), but it's not unbearable. Everywhere is air conditioned. The theme parks have wonderul cold water sprays randomly located around them and all theme parks have water rides which are great for cooling you down!! Most of them also have young kiddie areas where they can run through all sorts of wonderful water runs,and fountains, all very safe. With the heat, clothes dry very quickly!! We have been there with youngies of various ages - 1, 3, 5, 9. It probably is more pleasant in February or Sept/Oct but personally, I wouldn't rule it out for July. Enjoy!!