I usually go to WDW in December, but we surprised DD and took her for her 6th birthday. I probably came over-prepared for the weather, but, I did catch a few envious eyes looking my way!!
I ordered a set of 6 "Cool Wraps" from QVC. The are bandanas that can be tied around your neck, head or even wrist or ankle. You soak them in water for about 20 minutes and the crystals inside swell up and get ice cold. So, I soaked all six in the sink our first morning...then we took a soft, large cooler bag with us each day to the parks loaded with ice, water, box drinks, etc and I put the bandanas in it. When it got really hot we would tie one of those gems around our necks and they stayed cold for a few hours..then we would put those back in the cooler bag and get out the other 3 that were in there and use those...all day we had a cold bandana to use. HEAVEN
! That paired with a visor and mister fan made for enjoyable days in the Florida sun. The family we were with joked the heck out of me, but by the end of the week we were sharing them with them!!
BTW, the cooler bag was quite heavy to and from the parks, but once in, the rented stroller took that pain away!!
I ordered a set of 6 "Cool Wraps" from QVC. The are bandanas that can be tied around your neck, head or even wrist or ankle. You soak them in water for about 20 minutes and the crystals inside swell up and get ice cold. So, I soaked all six in the sink our first morning...then we took a soft, large cooler bag with us each day to the parks loaded with ice, water, box drinks, etc and I put the bandanas in it. When it got really hot we would tie one of those gems around our necks and they stayed cold for a few hours..then we would put those back in the cooler bag and get out the other 3 that were in there and use those...all day we had a cold bandana to use. HEAVEN

BTW, the cooler bag was quite heavy to and from the parks, but once in, the rented stroller took that pain away!!