Hi Danelle!
The last full week of July and first couple of weeks are August are still pretty busy at Walt Disney World, lots of guests are still visiting before the start of back to school in most areas of the country. Typically the level of attendance will slowly start to drop around the third full week in August because that is when many classes for students will start for the new school year.
In terms of weather, all three of these weeks are similar in temperature. The average high for those three weeks will be in the low to mid 90's, while the average low is around is in the upper 70's. Fortunately there hasn't been a hurricane to directly affect Walt Disney World in quite sometime, but you can expect for possible afternoon storms to pop up. I definitely recommend packing a poncho for any of these three weeks as pop up rain showers are very likely especially in the afternoon.
When trying to decide which of these weeks to visit Walt Disney World, I would decide based on what works the best for your situation. All three weeks will have similar weather and crowd levels so you may want to decide based on which resorts are available and possible discounts. Since you will have a little flexibility in your schedule, it will be much easier to find a discount at the Disney resort of your choice. Be sure to check out
Disney's Monstrous Summer Savings to save on your upcoming summer trip to Walt Disney World. I hope you have a fabulous vacation and please visit us again if you have anymore questions!
Happy Planning!
Mandy