If you haven't already, check out the Steven Harris interview with Jack on the subject of fuel storage, it's available on Steven's website:http://www.solar1234.com
As for storing gas, I don't have a shed or a garage either, so I use one of those large plastic garden tubs, designed to store things in outside. The gas cans go in there. It's in the shade.
Yes, it gets cold in the winter, but I think that's OK - so does the gas in my car's gas tank. Use something like the fuel storage additive that Steven Harris talks about, and yes I think it can store for 1 year, if you have it in a tightly sealed container (maybe rotating it out more frequently than once a year is a good idea, if you are using something like the standard red gas cans that are not very tightly sealed).
I don't have Florida heat up here in the Northeast, but it does get hot in the summer. Again, so does my car sitting in the sun all day long. If the gas is well sealed, from what I understand, it's not just going to spontaneously ignite just because it's hot. So I would think it's OK even in FL.