Complex sentence: Oviedo is located approximately to south of neighbouring cities Gijón and Avilés, which lie on the shoreline of the Bay of Biscay; its proximity to the ocean causes Oviedo to have a maritime climate, in spite of it not being located on the shoreline itself.
Split into simpler sentences: Oviedo is located approximately to south of neighbouring cities Gijón and Avilés, which lie on the shoreline of the Bay of Biscay. Its proximity to the ocean causes Oviedo to have a maritime climate, in spite of it not being located on the shoreline itself.