Given a chance, it is always better to paint your boat indoors. Indoors takes away so much of the guesswork. You have control over the weather and lighting and, to some degree, temperature. Indoor facilities for painting boats are somewhat limited and as the size of the boat increases, the availability of suitable sheds decreases. Hiring suitable facilities are going to add costs to your repair program. Another option is to construct a greenhouse-type structure over the boat; this will keep the weather away, but you will have to install a ventilation system to accommodate the fumes and dust associated with painting. Having your boat indoors for painting the topsides will give you a good advantage, particularly if you are spray painting your boat. The application of antifoul can be safely done outside, so to save costs, only use an indoor facility for spraying the topsides and superstructure.