What if it's raining, can I install heaters anywhere?
Many heaters are specifically designed to run in very wet environments and you will find several on this site that have IP ratings. An IP rating is a certificated confirmation that the particular unit is capable of working in either a dusty or wet environment. Any rating ending in a 4 or 5 i.e. IP65 is effectively completely weather resistant and can be installed in almost any outdoor situation.