Portugal is defined as a Mediterranean climate (Csa in the South, interior, and Douro region; Csb in the North, Central Portugal and coastal Alentejo; mixed oceanic climate along the northern half of the coastline and also Semi-arid climate or Steppe climate (BSk in certain parts of Beja district far South) according to the Köppen-Geiger Climate Classification), and is one of the warmest European countries: the annual average temperature in mainland Portugal varies from 8–12 °C (46. In the south of Portugal and on the Guadiana river basin, between what degrees does the average temperature fluctuate