We have gone to WDW in both February and August, and I can tell you that we love February and would never go in August again. We usually go during President's week, which is pretty crowded, but I understand that the crowds are low in early February, and the weather is so much more pleasant than in late summer. The weather can be quite variable in terms of temperature in February - for example, we have had days in the 80s and days in the low 60s. But if you plan to layer your clothing you will be fine. Also, February is one of the months of lowest rainfall in Florida, while it tends to rain often in the summer (when we were there in August it rained every afternoon). If you love very hot weather, and some people do, I'm sure you will be fine in August, but personally I can't stand the hot and humid summer and much prefer a cool weather trip. I'm sure that you will have a wonderful time whatever you decide.