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 in 1994, for around £750,000. The summits of the Cuillin are bare rock, jagged in outline and with steep cliffs and deep cut corries and gullies. Twelve Black Cuillin peaks are listed as Munros, though one of them, Blaven, is part of a group of outliers separated from the main ridge by Glen Sligachan. The scrambler can access most of the individual peaks by their easiest routes. Only the Inaccessible Pinnacle is a graded rock climb (Moderate) by its simplest line but several of the other summits require scrambling skills. Navigation on the ridge is difficult due to jagged terrain