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
Geology of Skye Part of the magma chambers for the volcanoes are exposed at the surface as major intrusions of gabbro and granite. These coarse-grained igneous rocks are relatively resistant to erosion and now form the Cuillin hills. The Black Cuillin are formed of gabbro, which erodes to form the characteristically jagged outlines, although this is in large part due to the many minor intrusions, such as dykes and cone sheets that cut the gabbro. The Red Hills are formed of granite and have a more rounded topography. All pre-Quaternary rock types on the island are affected by a major swarm of dykes,