Prestwick v St Mawgan weather alone I don't recall Prestwick being closed for weather in the 2 years I was there, not sure the same could be said for SM. As for wide open spaces and clear skies 'The Hebrides Range, set up in the 1950s, has sites on Benbecula, North and South Uist and a radar station on the remote St Kilda archipelago.The range offers the largest area in the UK for the live-firing of rockets and missiles.