I had never thought about this before: The relative difference between the air and water temperature in Scotland is less in autumn and winter than in summer. Which means that getting into Scottish seas in a wetsuit in autumn might not be such a unsavoury prospect. It will still be cold but it might not feel quite as cold as you imagine.
Added to this, the summer usually warms up Scottish seas and there is a higher chance of better and more consistent swells and waves. All this means that now is a good time to go surfing. I have written more about this in my Sunday Mail outdoors column.