Im not an expert but if you look on Lanny's map it shows the bottom third of florida is not normally in the breeding range but he still has two dots in extremely southern florida. All I can say is have the feeder out and maybe it will stay.

Here is a link that might be useful: hummingbird map

If you go to www.hummingbird.net, this is a site that Steve has for people in Florida. Post there and I am sure you will get more feedback. He lives nears Valicro and several of my friends here in Lakeland had birds till just recently.

Make that Floridahummingbird.net