Installing a fluorescent light in my patio?

The previous answers addressed questions 2 and 3 so I will focus on question 1. How well they will work in the lower temperatures depends on if you plan to use CFLs (screw in fluorescent lamps similar to incandescent) or linear type (4 foot straight tubes). The CFLs will start slower and have a slightly lower light output at lower temperatures compared to the linear types. You will have much better luck with the linear types and you want to use commercial grade fixtures with a Program Start type ballast. Typical fixtures have Instant Start or the old Rapid Start type ballast which will work in cold temperatures but the new Program Start type ballast will work better. I have seen T8 fixtures with a program start ballast installed in commercial Ice Cream freezers (-24 F) and they are on motion sensors so they cycle on/off. They start instantly at 70% of full light and are at full light output in 2-3 seconds. Since these are normally considered commercial grade lights, you will find these ballast and fixtures at electrical or lighting distributors. Large hardware stores typically do not carry them.