We won't be relocating but if we were, I would start by looking for stability and safety. We don't need our retirement lives disrupted by some future natural disaster. I would completely rule out areas subject to hurricanes, wild fires, earthquakes, extreme cold or heat, floods, etc. I would also avoid areas with actual or impending drinking water availability issues, like LA and Phoenix. I would be less concerned about tornadoes because they are "spot" disasters, not area disasters. Some decisions, like the Gulf of Mexico, the SE Atlantic coast, and known earthquake zones like the San Andreas fault are no-brainers for me but YMMV.