Portugal is a sovereign state located on the Iberian Peninsula in southwestern Europe. It is the westernmost country of mainland Europe. Portugal is defined as a Mediterranean climate, and is one of the warmest European countries. Portugal has around 2500 to 3200 hours of sunshine a year, an average of 4â6 h in winter and 10â12 h in the summer. Portugal has been a semi-presidential representative democratic republic since the ratification of the Constitution of 1976. A member state of the United Nations since 1955, Portugal is also a founding member of NATO (1949), OECD (1961) and EFTA (1960). It became the European Union in 1993.