Florida doesn't get too cold so I wouldn't budge purchasing maternity. But if you decide to purchase head to h&m ASAP. I went yesterday and they had almost all maternity 40% and 50% off. ;)
I live in Florida too, i didn't buy maternity clothes my time around and I was pregnant through summer, this time i will be pregnant through winter and probably won't buy maternity clothes either, yoga pants and stretchy shirts like last time.
I live in Oregon. Weather is much different. Honestly, you will more than likely be able to wear the same things you would wear not pregnant. If it hits winter and your wardrobe isn't doing it, then go out and buy what will. Probably best to wait.
Oh, leggings are good too. They look nice with the tank/cardigan outfit. Whatever is comfy and you feel would be functional for you. We're all different, I already enjoying wearing outfits like this. I just have to make sure to purchase maternity tanks. :)
I'm due December 6th. I'm buying tank tops for summer and I will throw a cardigan over my tank tops during the winter months. I've also purchased a sweater at a thrift store. I've never been pregnant, but I believe layers are best. A comfy tank with a heavy cardigan is always a nice comfy look.
Maybe just stick to yoga pants so you can wear them afterwards too, atleast I was able to my first time.
Does it get cold there before December?