Rùm rest of the British Isles and Scotland, Rùm features a strongly maritime climate with cool summers and mild winters. There is a MetOffice weather station at Kinloch providing long term climate observations. The main range of hills on Rùm are the Cuillin, usually referred to as the "Rùm Cuillin", in order to distinguish them from the Cuillin of Skye. They are rocky peaks of gabbro, forming the Rum layered intrusion. Geologically, Rùm is the core of a deeply eroded volcano that was active in the Paleogene era some 60 million years ago, and which developed on a pre-existing structure of
Cuillin and magnetic abnormalities that make compass reading unreliable. The majority of scramblers heading on to the Black Cuillin do so via routes from Glenbrittle (where there is a campsite and a youth hostel) or Sligachan for the northern peaks: due to the remoteness of Loch Coruisk, which can only be reached by boat or a "c." 10 km walk from Elgol, routes starting from this side are less frequented. In addition to climbing individual peaks, there is the challenge of a full traverse of the main Black Cuillin ridge. Although only in length, the average traverse is likely to take