We've gone once in August, the exact same time period you're considering (last two weeks). There tend to be some decent Canadian discounts for that time period, if you stay on site (in the past, I think there's been a Canadian-only free dining option? And decent room only discounts too). The crowds are definitely manageable, too, and might be similar to what you've experienced in early Dec. But it definitely is hot, humid, and very different from a December trip. For us, the hardest days were the ones where we tried to accomplish too much. My advice (take what's useful! hah):
- plan a break every afternoon. Sometimes our break was actually late morning, to be honest: rope drop followed by a late-morning break, then back to things for the afternoon/evening. We tried to be either indoors or in a swimming pool during the hottest parts of the day. This meant lunch was often our biggest meal of the day, usually at a TS restaurant with air conditioning.
- drink more water than you think you need. We always carried brita bottles and filled them at QS restaurants around the parks. Takes the funny taste away.
- If you're in Florida for 2 weeks, pace yourselves. Build down days into your plan. I highly recommend the waterparks at this time of the year.
- bring at least 2 pairs of shoes each. Our feet swelled in the heat, and it was important to have different footwear options to allow for the swelling.
Phew! I hope this helps!