For most people a converted attic is not noisy in rain or wind. Modern rooflights are double or triple glazed, and once the room is insulated the sound of weather is much softer than you might expect. It is a common concern, but rarely a real problem in day to day living.
Rain on the glass is the sound people ask about most. In light or moderate rain it is usually minor, often no more than a gentle background patter. In genuinely heavy rain it is audible, and some people even like it, but it is not disruptive for the great majority of occupants and it is nothing like the drumming you get on an uninsulated shed or a bare roof.
Wind is generally a non-issue in a well built conversion. The insulation and the sealed rooflight units dampen sound, and correctly fitted flashings mean there is no rattling or whistling. If wind noise ever does appear, it usually points to a seal or flashing that needs attention rather than anything inherent to attic rooms.
If you are a light sleeper and want to minimise any noise, choices at design stage help: triple-glazed units, and rooflight placement away from the sleeping position in a bedroom. We can factor that in. See our rooflight conversions and dormer conversions, or book a free assessment to talk through your layout.