We don’t live in Florida, but we do often head to some tropical locations, so I have a variety of cooling fans and instruments, as well as things to keep dry in monsoon weather.  Things I don’t recommend, specifically for this purpose: 

• Wearing sandals.  My first instinct was, if it rains, or I get wet, of course I don’t want to be wearing socks and shoes.  But shoes getting wet is a ‘maybe’, while walking thousands upon thousands of steps is a ‘for sure’.  So unless your sandals are capable of being worn for miles and miles of walking and standing without digging blisters into your feet, don’t.  If you’re extremely paranoid, you can carry these Japanese shoe covers when there’s threat of shoe splashes.  

• Powered hand fans.  The heat in Florida is a heavy, wet, sticky thing.  A little hand fan is going to do precisely squat, and is heavier than other options (but this is the one I do recommend for other hot areas of the planet).  Once again, your main enemies are 1) being outside, and 2) walking a lot; a hefty battery-powered device is going to weigh you down more than cool you off.  As an alternative, I’d say one of those extra-light circular nylon hand fans will do a more effective job while being as weightless as possible. 

• Umbrella.  I have many varieties of umbrella for travel, some medium, some tiny and packable.  And in other areas of the world, these are perfectly effective and a solid weight-to-usefulness ratio.  Not Florida.  Rain comes down in buckets, and if you’re carrying any size umbrella less than “ultra-grand”, your shoes will be soaked in seconds.  And if your shoes are soaked, what’s the point in any of the rest of you staying dry?  Your top is sweaty, anyway.  As for the gargantuan models that would keep all of you dry, well those certainly don’t fit in a bag, so you’d be carrying around a huge weight in one hand, just to run around jabbing other guests in the eyes with the tines when you go to actually use it.    

Things I do recommend: 

• Cooling towel: weirdly, I searched high and low around Orlando for one of these, and could not spot any for sale in the regular stores, which were otherwise brimming with beach and sun gear.  Odd, maybe I missed it?  I definitely saw some inside Disneyworld, and they were easily twenty bucks.  So… buy ahead, I guess.  All you need to do is wet these with any kind of water (plenty available around all theme parks, and if you can’t find any, just ask an employee.  I’m sure it’s criminal to deny people water in the heat and swampness of Florida) and then shake it out before applying directly to your face or neck to get some direct cooling relief.  Yeah, you may get damp or wet, but surely you already were in the sweltering heat.  If you can find ice cold water, it’s extra effective, so pair it with some ice at the bottom of your cooler backpack, listed below.  It’s the most direct way I’ve found of immediately lowering my overall body temperature, and it’s super portable, since you can pocket it or tie it to a bag when you’re not actively using it.

• Cooler backpack: as mentioned above, this is mainly for Disney, which allows you a good-sized bag on many rides, and also seems fine with bringing in food.  Avoid when going to Universal, unless you have someone in your party that will hold it while you’re on rides, because ours did not compress down enough to get into one of their tiny ride lockers.  Also, as mentioned just above, this pairs perfectly with the cooling towel to keep drinks ice cold and cooling towels super effective.  The backpack style is important to me, because the weight of drinks and ice, coupled with a lot of walking in the sun and standing in line makes me want two padded straps instead of a one-shoulder tote for all-day wear.  The best backpacks have mesh-lined backs and shoulder straps so you don’t get too hot, but sweat is pretty much inevitable on most days in Florida.  And the backpack I have boasts thick insulated walls that will keep ice in solid form for hours, even in the sun and heat.  And actually having an ice cold drink on demand is amazing when you’re sweaty and gross.  We broke out our drinks once we found seats at the Indiana Jones Stunt Show, which I highly recommend, because well first of all, it’s still a fun show.  Aside from that, it’s outdoors, but shaded.  On the day we were there, it was not terribly crowded, so it felt like a great time to break out some snacks and cold drinks, as it’s a 30 minute long show, and we got there at least 20 minutes early. Back to the cooler bag, overall I’d say they are effective, but quite heavy, so share the load by passing it back and forth, or hope you have a very sturdy person in your party that’s willing to carry it around all day. 

• Giant poncho: I watched enviously as other Disney guests pulled out ponchos and continued about their day, while the rest of us huddled forlornly under building eaves and umbrella stands to wait it out.  Remember, to be actually effective, it has to be a super thick and oversized poncho, which means it’s going to take up some significant space in your bag, but if you’re going during the season of heavy rain, don’t underestimate how necessary this is.  Florida rain comes down in huge plopping buckets, and will soak every part of you in moments.  A generously-sized poncho will cover you, your backpack, and drape safely over your shoes, so hopefully they will stay relatively dry.  This one has a built in pouch feature to keep your phone available and dry.  And I like the snap-sides that let you adjust it on the fly and shake it dry a little bit easier than ones that have sewn sleeves.