You might get by with it. If you look up more info on the web, you'll find that the more sun the better. Watch out for hard frosts or low temps too. Might need to look into protecting them. I would post your question on the Tropical Fruit forum. Some of the Fl guys would be able to answer this better than I.

It's hard to make mangos thrive where the temps drop below 35 F. It will need cover not only for the frost but just the regular cold weather. However, if you just want a small tree that will produce a few pounds a year, you may be able to get away with the climate.
As for the sun, ohio is right: it will suffice, but considering the climate, the more sun the better (8-12 is the best for most).
Don't stress over the dwarf thing, any variety can be pruned to a small size, find a variety you like, and that will tolerate the temps, and prune. Also, the older and more established the tree, the more cold hardy it becomes, don't know your budget or timing, but I would get a larger plant (above 15 gal) and plant in a year that the temps are not low (as early as you can).

Thanks for the input. Last week I visited a nursery on Pine Island NW of Ft. Myers (NOT Pine Island Nursery) and there were mangos growing in light conditions similar to mine. The owners said I would get fruiting on the more sunlit sides of the trees. Cold is not an issue with me although the last two winters were very cold throughout FL. Generally it lightly freezes once every 4 or 5 years in my area. The coldest I have ever measured in my yard (12 years) is 27F on 1/10/11. There are very large mango trees, perhaps to 50 feet tall, throughout the area.

As an aside, try to keep the tree open by judicious pruning. This will mitigate mildew on the flower trusses. Here, it invariably rains just as the trusses come on. Planting where the morning sun strikes it early would help (like roses). And good luck!

Thank you for the replies. I'm a newcomer to mango culture and wound up with four trees spaced 12 feet apart. They will be kept trimmed and two of them are naturally small anyway (Pickering & Nam Doc Mai #4). Mangos must not be as sunlight critical as I had believed. I have since observed bearing trees in what I would call partial sun locations, less open than mine.