Geography of Portugal - Climate

Climate

Most of Portugal has a Mediterranean climate according to the Köppen climate classification: Csa in the lands south of Tagus River, inland Douro Valley in the North and Madeira Islands. The Csb pattern can be found north of that river, Costa Vicentina in coastal Southern Portugal, and the eastern group of the Azores islands. Most of the Azores have an Oceanic climate or Cfb, while a small region in inland Alentejo has Bsk or semi-arid climate. The Savage Islands, that belong to the Madeira archipelago, also has an arid climate with an annual average rainfall of around 150 mm (5.9 in). The sea surface temperatures in these archipelagos vary from 16–18 °C (60.8–64.4 °F) in winter to 23–24 °C (73.4–75.2 °F) in the summer, occasionally reaching 26 °C (78.8 °F).

The annual average temperature in mainland Portugal varies from 12–13 °C (53.6–55.4 °F) in the mountainous interior north to 17–18 °C (62.6–64.4 °F) in the south (in general the south is warmer and drier than the north). The Madeira and Azores archipelagos have a narrower temperature range with the annual average temperature sometimes exceeding 20 °C (68 °F) in the south coast of Madeira Island. Extreme temperatures occur in the mountains in the northeast of the country in winter, where they may fall to −15 °C (5 °F), and in southeastern parts in the summer, sometimes exceeding 45 °C (113 °F). The official absolute extreme temperatures are −16 °C (3.2 °F) in Penhas da Saúde on 4 February 1954 and 47.4 °C (117.3 °F) in Amareleja in the Alentejo region, on 1 August 2003. There are, however, unofficial records of 50.5 °C (122.9 °F) on 4 August 1881 in Riodades, São João da Pesqueira. It's very plausible since this region is known for its microclimate. The annual average rainfall varies from a bit more than 3,000 mm (118.1 in) in the mountains in the north to less than 600 mm (23.6 in) in southern parts of Alentejo. Portugal as a whole is amongst the sunniest areas in Europe, with around 2500–3200 hours of sunshine a year, an average of 4-6h in winter and 10-12h in the summer, with higher values in the southeast and lower in the northwest. The sea surface temperature is higher in the south coast where it varies from 15–16 °C (59–60.8 °F) in January to 22–23 °C (71.6–73.4 °F) in August, occasionally reaching 25 °C (77 °F); on the west coast the sea surface temperature is around 14–15 °C (57.2–59 °F) in winter and 18–20 °C (64–68 °F) in the summer.